Blender 3D Tips, Reference, Cheatsheet

This is an article containing Blender Tips and Reference List (Cheatsheet) that I compiled from my own studies for my own reference.  I decided to post it here for easy access.  This may vary from version to version, so it might not be 100% accurate.  Use Ctrl+F on this article to find stuff.

____ Blender Basics ____
> It seems that the green y is the back.  Opposite green dot is front.  Use Numpad to control (see below)
> Parenting...
--- to add a parent: select child, select parent, Ctrl+P
--- to remove parent: click on child, Alt+P

____ Blender Hotkeys ____
More at: https://www.katsbits.com/tutorials/blender/useful-keyboard-shortcuts.php
> Mouse
--- Right Click to select things, unless swapped.  Shift+RClick for multiple
------ In edit mode, Ctrl+Right Click (after selecting something) does a path select
------ Shift Right Click adds or minus selection
------ Alt+RClick to loop select (with another selected to determine axis).  Alt+Shift+RClick to add new selection loop.
--- Middle Click for view purposes:
------ MClick drag rotation
------ Shift+MClick drag Strafe
------ Alt+MClick to pan (Good to change it to semicolon)
------ Ctrl+MClick drag to zoom
------ scroll also to zoom
--- Left Click to confirm an action (like Enter in LW)
------ LClick drag to transform stuff (handles)
------ Ctrl+drag to loop select in Edit mode (ANY MODE OTHER THAN SELECT MODE).  Dragging nothing also deselects stuff
> Numpad is powerful.
--- Numpad 1234679 for different camera angles.  
--- Numpad 5 for Orthographic.  
--- Numpad 9 for switching to the opposite side?
--- Numpad . for centering. 
______________________________________________
| TopView   |   Upward  |   Reverse |Zoom out |
|___________|___________|___________|_________|
| Leftward  |Orth Tog   | Rightward |Zoom In  |
|___________|___________|___________|         |
| FrontView |Downward   | LeftView  |         |
|___________|___________|___________|_________|
| CameraView            |Centering  |
|_______________________|___________|

 +/- for zooming
> Transforming
--- Ctrl+Space = transform manipulator
--- G = free Translate/Manipulate (X, Y and Z to lock axis) (keep toggling G to switch axes?)
--- S = free Scale/Resize (X, Y and Z to lock axis) (keep toggling G to switch axes?)
--- R = free Rotate (X, Y and Z to lock axis) (keep toggling G to switch axes?)
--- Alt+G/S/R to reset
--- "Clear Transform" for poses?
--- +Ctrl = Snaps to increment (^)
--- +Ctrl +Shift = Snaps to smaller increment (^)
--- +Shift = Slows movement (^)
--- +Shift +Ctrl = Snaps to smaller increments (^)
> Important
--- Spacebar for shortcut search
--- Home to recenter view to objects
--- Alt+Home to recenter to the cursor (life saver rubber ring)
--- Ctrl+Z = Undo
--- Shift+Ctrl+Z = Redo
--- X = Delete
--- Z = toggle Wireframe/Solid viewport shading
--- A = select/deselect
--- Shift+C = reset 3d cursor to center

____ █ Blender Origin, Pivot, Cursor Stuff ____
> Shift+C set cursor to World Origin
> Shift+S set cursor to ...
> W, O set origin of an object to ...
> Transform Location (right side panel) to type in location to set

____ Blender Techniques ____
> Duplicate: Shift+D, click or Escape to confirm.  Note: if you duplicate a collection, materials and textures will still be shared!  To make them unique, go the material tab and click on the number next to the name and it will create name.001.
> Make new instance: Alt+D (not duplicate)
> Mirroring:  Select (Edit mode or object mode, whatever), duplicate it (optional), Shift+C to put cursor in center, set cursor as pivot (next to Global dropdown top right), Ctrl+M, press x/y/z depending on which axis you want (not the divider axis)
> Mirrored bone naming: Shift+C to center cursor, cursor as pivot (next to "Global"), select bones, press W > Symmetrize.  Everything left will go right, names changed accurately.  Flip names are ok but you need to duplicate first, and then it will have 001.
> Inserting characters in a scene:
--- seems like you need to use Append, select the blend file (which will open up an internal folder), then select Collection.  (not sure about the scripts)
> Inserting characters in a scene 2 (non-append, like LW):
--- Using File > Link, and select Collection.  Other things like meshes will just be immovable
--- After changes are made, to see changes, go to File > Revert
> Using Proxy to animate Linked objects:
--- Select it and then Ctrl+Alt+P for Make Proxy.  (For Armature)  It becomes editable and posable.
> Make an instance: select the collection, Rclick > Duplicate Linked.  You should be able to drag it to wherever you like and editing it will edit everything.  It will have a .001 name behind it
> More about linking, instances: https://blender.stackexchange.com/questions/51128/file-optimization-duplicate-or-linked-duplicate

____ Blender Modeling ____
> 3D Cursor set position : View Tab > 3D Cursor
> Add Stuff : Shift+A
> Add Vertex : select an edge, W, subdivide
> Apply Rotation, Apply Scale, Apply Location to the actual mesh : Ctrl+A when an object is selected
> Bevel : Ctrl+B
> Break : see Detach
> Bridge edge loops (cut holes or create tubes from rings or connect) : select 2 opposite faces and then Bridge Edge Loops (search) (may need to Ctrl+N to unify normals)
> Copy selection / Spawn new object from selection / Separate selection : Select faces... Shift+D, Esc to duplicate, P > Selection
> Cursor controls: Shift+S
> Delete Faces : X, F
> Delete Vertices : X, V
> Detach edges (Tear) : V?
> Dissolve Vertices (delete without destroying polys) : W, D
> Deselect all : AA
> Detach polys : Y
> Even spacing : "Space"
> Extrude : E or select something and then Ctrl+LClick somewhere else! (can also do inset)
> Falloff : Use Proportional editing (somewhere near "Global").  Then pressing G/S/R will have falloffs (circle).  But if there is no circle, just scroll up until you see it.  Good to select some vertices of faces first as the drag base, and use 3d cursor as the anchor (set cursor as pivot)
> Hide Vertices : H.  Unhide with Alt+H
> Inset : I
> Knife : K and then click on one edge, drag to the other edge.  Press C to constraint straight lines 45 degrees. Pressing Z cuts through the other side.  Without it, it just cuts the front face.  When active, the text at the bottom shows what to press.
> Lathe : See Spin tool
> Loop Cut : Ctrl+R and mouse scroll for more
> Make Poly : F
> Merge Polys : F
> Merge Vertices : Alt+M
> Merge Vertices close together : Select affected polys, Ctrl+1 to vertex mode, Alt+M --> by Distance
> Move : G or Move Gizmo (gizmo is better; RClick the button and assign a shortcut [Shift+T], and if using 3D cursor as pivot, just click anywhere near as the gizmo will be centered on the cursor )
> Normals flip : search for "Flip Normals"
> Normals unify : Ctrl+N
> Origin to middle of geometry : Object mode, Search for "Set Origin"
> Origin to one side of geometry : Edit mode, select a face and Shift+S > Cursor to selected.  Object mode, "Set Origin" > Origin to Cursor
> Pen tool : Actually it's just like extruding vertices.  Must be in orth view (7/1/3) Create a mesh (plane preferred), rotate it a bit, delete all but one vertex, select it, ctrl+click...
> Pole : no tool for this.  Select all edges of the hole then E, S, 0, Alt+M,B (remove doubles/merge by distance)
> Rail Extrude for Ropes, snakes, etc : Nurbs curve + nurbs circle, and in the nurbs curve tab, choose a bevel object! https://www.youtube.com/watch?v=SVzRaYxq1io
> Remove Doubles / Merge by Distance (double vertices, etc) : Alt+M,B
> Rotate : R or Rotate Gizmo (gizmo is better; RClick the button and assign a shortcut [Shift+Y], and if using 3D cursor as pivot, just click anywhere near as the gizmo will be centered on the cursor )
> Scale : S or Scale Gizmo (gizmo is better; RClick the button and assign a shortcut [Shift+6], and if using 3D cursor as pivot, just click anywhere near as the gizmo will be centered on the cursor
> Select a grid face : select one corner and Shift+Ctrl+RClick the other corner
> Select Inverse (invert selection) : Ctrl+I
> Select linked/connected : L
> Selection mode toggle (Vertices/Edges/Faces) : Ctrl+1/2/3 (Blender 2.8)
> Settings for (some) tools: F6
> Spin Tool : select a polygon and spin it.  Will follow 3D cursor as pivot (position it accordingly before hand.
> Split Edges : Knife : K
> Subdivision modifier add (object mode only): Ctrl+1/2/3/4/5/6
> Symmetrical Editing:
--- model has only half of the mesh and the Mirror Modifier is used.
--- X Mirror at the Right side menu Tool tab can work without mirror modifier.  But must be very accurate.
> Tris to Quad : Select polys and Alt+J or Ctrl+F > Tris to Quad
> Triple Polys : Ctrl+T
> UV Unwrap : use Smart Project and island margin around 0.1

____ Blender Modeling Pivot and other Techniques ____
> Set pivot point to cursor first
> Activate Cursor tool : Need to assign it by Rclicking the button (Set it back to Ctrl+Alt+Shift+C?)
> Cursor move to selection : Shift+S, 2  (##important)
> Selected to cursor : Shift+S, 7 or Shift+S, 8 (messed up)  (##important)
> Edit mode Origin move:
--- Origin to 3D Cursor : W, O, T (##important)
--- Origin to Object Geom : W, O, O
--- Origin to Surface Center : W, O, C
--- Origin to Volume Center : W, O, M
> Get ready shortcut keys for translate, rotate and scale gizmos (recommended Shift+T, Shift+Y, Shift+6) which will work in unison with the 3D cursor
> Shift+A also determined by Cursor position
> Snapping:
--- hold down Ctrl to snap
--- hold down Ctrl+Shift to snap to smaller increments
--- can change the snapping mode near magnet icon (the one on the top part of the screen).  Grid snap has "Absolute Grid snap" option to align with grids perfectly
--- vertex snapping can automerge (auto merge), in N panel > Tool tab > Auto Merge (below X Mirror)
--- face snapping "Align Rotation to Target" option will help place objects on mesh (object on object?)

____ Blender Morphs (Shape Keys) ____
> At the vertices (3 dots) tab under Vertex Group
> Create at least 2.  (Object Mode only)  One for the base!
> You can make adjustments as you like, even add vertices and edges, it seems! (only in Edit mode)
> See them in action by adjusting the value (object mode)
> Transferring shape keys from one object to another with different vertices require ShapeKeyTransfer plugin and Blender 2.8 https://www.youtube.com/watch?v=-zBlaedkkVs
> After making new changes on the basis, shapekeys are affected but the shapes are not the same.  To fix:
----select your destination shape key (it should be a copy of the basis), then go into 'edit mode'
----select the vertices you want to move.  (sometimes it can only be found at origin point)
----press [ctrl]+[V] and 'blend from shape'
----press [F6] or look at the bottom of the [T] tool shelf for the context menu, change the key to the 'source' shape key you want to copy from.  May want to uncheck "Add". If you are not working from 'basis' you may need to adjust the 'blend' to better match the shape key you are blending from.

____ Blender Materials, Surfaces, Textures, UV Maps ____
> multiple stacked png textures: https://www.youtube.com/watch?v=Pr1byNDZNko
> Without UV Map, like Lightwave Basic:
--- click on a material or add a new one, then click the New button.
--- using nodes, link an image texture to the base color.  Then add a texture coordinate node's generated to a Mapping node's Vector in and the mapping node's vector out to the image texture's vector in.
--- Mapping node is set to Texture, and image texture set to linear and box (or anything else suitable)
--- to switch to UV map, go to materials tab and change Vector from mapping to UV
> Using nodes for image and normal Map:
--- UV must already be unwrapped based on the image
--- create new material (round checkered thing tab) --- optionally switch to Toon BSDF and 0.01 size and 0-0.125 smooth if desired.
--- click "Use Nodes"
--- in a separate panel go to Shader Nodes section, shift+A to add 2 image textures and normal map.  
------ image texture color to bsdf color, 
------ normal texture color to normal map color, 
------ normal map color to bsdf normal.
------ for transparency (above another material) [TRANS], add this: (A) alpha image node (A2) bg image node (B) mix rgb node (C) BSDF base color.  A color -> B bottom color.  A alpha -> B fac.  A2 color -> B top color.  B color -> C base color
------ for transparency (polygon see through) (cycles render only), add a mix shader node in between bsdf and material output... then switch the link so that bsdf shader uses the bottom shader dot.  Add a transparent bsdf node and plug it to the top shader.  Link the image texture's alpha to the mix shader's fac
------ for transparency (eevee render), need to do all the above and then go to Material tab > settings > Blend Mode Alpha Clip
> Double-sided or single-sided surfaces : Material Tab > Settings > Backface Culling??
> Glass : change to Glass BSDF shader and tweak settings (roughness 0 for plain glass)
> Glass window: must not use Glass BSDF!  Instead, must do a complex node setup:
--- Nodes: Light Path, Math1, Math2, Mix Shader, Mix Shader, Fresnel, Glossy, Transparent
--- Light Path shadow ray to Math1 value1.  Light Path diffuse ray to Math1 value2.  Math1 value to Math2 value1. Light Path glossy ray to Math 2 value 2.  Math2 value to MiX2 fac.  Mix2 shader to Material Output surface.  Fresnel Fac to Mix1 fac.  Glossy bsdf to mix1 shader1.  Transparent bsdf to mix1 shader2.  Transparent bsdf to mix2 shader2.  mix1 shader to mix2 shader1.
> Using turbulence / generated textures... Voronoi texture node with Ctrl+T, color ---> Mix Shader Fac.  Principle BSDF ---> Mix shader bottom color.  Mix Shader ---> Material Output Surface
> Smooth Shading -> object mode select the object, click Object > Smooth Shade.  To retain some hard edges, in edit mode, select the edge and Ctrl+E > Mark Sharp.  To get rid of the sharp, Ctrl+E > Clear Sharp.
> Ambient Occlusion (detail at the creases)

____ Blender Image Texture control using UV Project Modifier (Anime Eyes) ____
> Add image to be projected in the texture area.
> New Material for the object, node the image texture to it (clip instead of repeat).  For alpha image, refer to the alpha transparency texturing section.
> Make a camera and point it to the object.
> Add a UV Project Modifier on the object and select the camera as a projector.  Can adjust scaling there.
> Note: green eye hole masking eye pupil doesn't seem very possible.  Either go with baked eyes or 3d eyelids...  

____ Blender Rendering ____
> Cycles is slow but nice.  Adjust samples to low values for faster output.
> To adjust color look, go to  Scene tab under Color management, switch to Filmic for higher hdr or RAW for cartoonish/anime.
> Too much noise/dots... go to View Layer tab (pieces of photo) and check Denoising (post render only).  May have drawbacks... too little render samples, distortions may occur
> Dimensions/Resolution can be found under Output tab.
> Rendering outlines using Freestyle Line Set.  Enable it at Render tab, then make adjustments at the Context layer (crease angle)
--- Everything will be lined, but to exclude some things, need to use groups or different render layers https://blender.stackexchange.com/questions/82086/how-to-exclude-an-object-from-freestyle-render
> Camera mode toggle: Num 0 (N panel View tab Lock Camera to enable in-cam controls)
> Toon Render: Render Tab > Use Cycles.  Material Tab > Toon BSDF, size 0.01 and smooth 0.  World Tab > Choose Surface Background color.  Light Tab (Select the light) > Select desired type and brightness.  Add new light for more highlights.
> Shadows turn off : Eevee only, it seems.  Material Tab > Settings > Shadow Mode None
> Camera don't render outside the border: Output tab (Printer) > Dimensions > Render Region
> To speed up rendering:
--- Reduce Light bounces: Set the Min to 0 and Max to a low setting
--- Change tile size : Scene Tab > Performance section > Tile Size (bigger tiles faster using GPU.  Smaller tiles faster using CPU)
--- Reduce samples (but the article recommends 2000 samples)  Can use lower samples but with denoising
--- GPU render: File>User Preferences > System and under Compute Device, check CUDA. Then in the render panel you will have the option to change the device to GPU
--- Make sure progressive refine is disabled (under tiles)
--- https://www.blenderguru.com/articles/4-easy-ways-to-speed-up-cycles

____ Blender Lighting ____
> World light: it's said that there's no need for a sun light.  Just use the environment texture or world color...?  
> Lamps: create a 3d model and color it with a material but change the surface from Principle BSDF to Emission.  Can adjust the strength to a big value!  But, may need superb rendering power
> No light but not dark : Ambieny Occlusion is the culprit

____ Blender Bones, Rigging, Armature ____
> To create bones, Shift+A or use E on selected bone.  For adjustments, use Normal Orientation in right side panel tools.
> Fast bone centering: After creating the first bone, enable snapping(magnet), snap to volume and median.  When you create bones, they will be centered in the middle of geometry ( https://www.youtube.com/watch?v=MWr5UqPSSxE )
> For each bone, from time to time, need to:
--- recalculate roll so that it's not messed up (see below, but mostly Shift+N, Global Z)
--- (seems to be limiting...) Add constraint in Pose Mode (Ctrl+Shift+C, limit rotation, Convert:Local Space)...  Or select multiple bones, add a constraint (only one bone will be selected) then click Pose > Constraints > Copy
--- (optional) change rotation type to XYZ Euler in Pose Mode right panel Item tab, (Select all bones and Ctrl+R) but it seems that Euler is not so good
--- rename (some with .L at the back)
> Recalculate roll for bone : Shift+N and choose the axis that is horizontal to the view.  Don't use Local. For example: green line from left to right = Global Y axis ( https://www.youtube.com/watch?v=MWr5UqPSSxE )
--- this is important to make bones rotate parallel to the right axis!
> Bones Clear Roll / Clear Rotation (Alt+R)
> Bones Symmetry adjustments (in the tool panel on the right, there's an X Axis Mirror)
> Change Bone style: can only be changed in the armature section, selected in object mode.  Viewport display stick, etc...
> To avoid gimbal lock, a possible solution is to use a small gimbal pre bone that controls X and Z.  The real bone controls Y (green) or preferably the roll.  If no luck, use Quarternion.
> Constraint rotation: Add Bone Constraint in pose mode (funny bone icon), but make sure Convert is local (not with parent) and not World
> IMPORTANT: To check and rotate bones properly in Pose mode (posing), in the N panel tools tab, set orientation to Gimbal.  Also good for Edit mode adjustments! (Orientation Normals)
> IMPORTANT: traverse select bone hierarchy up and down using [ nad ]
> Assign armature(bones) to an object/mesh: Select object, shift click armature, Ctrl+P.  Can use automated weights (may need to preserve volume in the modifier side tab for some sort of muscle flexing thing) and you can also use empty weights. 
  But some bones like root bones and ik bones must not deform the model, so in the bone tab for them, uncheck Deform!

> Regarding Joints:
--- the best would be using 3 lines cut.  The bone joint point should be on the center line.
> Regarding Weightpainting:
--- it seems that automatic weights paint too smooth.  Harder borders are desirable for better bending.  Need to repaint using weight painting.  For buttocks, the butt cheek should be 0.2 weight (light blue).
--- rule of thumb: outer bends are light blue.  Inner bends should be hard cut red and dark blue.

____ Blender Weight Paint ____
> Just click the dropdown to go to weight paint mode
> Remember that the paint is on the vertices and not the faces.
> To pose and paint (adjust pose when weight painting), go to Object mode, select the Armature, shift select the mesh, go to weight paint!  You can pose using the G and R keys (gizmos not available, it seems)

____ Blender Drivers and Custom Properties ____
> Add new custom properties in the right side panel after clicking on an item.  Can set name and tooltip and min max default values.
> To use the custom property, can assign drivers to the required object and the custom property as controller.
> RClick on the required object/node's property > Assign Driver.  (Clicking Edit Driver will bring up the box.  Selecting the object/node and going to Drivers window and clicking on the right side Drivers tab can also access the driver editor.)
> In the top part, change type to Scripted Expression.
> In the Input Variable below, change dropdown to Single Property and type in a variable name (any).
> For prop, change dropdown to Object or whatever item that needs driving, and select the item (make sure it's the right one!)
> As for path, type in the path (copy path data) or just use this format: ["customPropertyName"]
> Back to the top part Expression, it is just programming.  use variableName (from the top) +/-/* etc......
> Test it out.
> For the eye/face sprites, 
--- make a 3x3 plane, 
--- shrink wrap it to the face, 
--- assign a "sprite sheet" material to it, (preferably the default sprite is at the bottom if sprite sheet is vertical and left if the sprite sheet is horizontal)
--- Ctrl+T on the image node to get controls,
--- adjust scaling and location,
--- determine the location axis that changes the sprite, and by how much <moveHowMuch>
--- create custom property for the 3x3 plane (no decimal)
--- assign that custom property as the driver to that location axis.  Expression: variable*moveHowMuch+initialvalue

____ Dillony Workflow ____
NOTE: harder and more tedious than expected to create a good realistic progenitor
> Have an object ready (facing FRONT face, XYZ 000, Rotation 000, Scale 111)
> Shift+A and add base bone (Armature)
> Adjust snapping to Median/Vertex
> Alt+G to center the bone to Mesh
> Edit mode, drag its head where desired.
> Press E to extrude a new bone.
> Optionally, Alt+P to detach it and Ctrl+P to join it back as detached bone
> Note: 2 bones needed for the neck, it seems.
> Position the bones, once all are done, optionally limit axes (bone constraint section, works for non-ik only. Up is 90 degrees and right is 0 degrees.  Vertical spine limit x center 90d, z center 0d [-20/+20], y fixed), Shift+N (recalculate roll) where needed
> Rename bones, some with .L extension
> Make 2 IK bones and 2 pole bones. (not parented to limbs, but Pole parented to IK!!)  IK facing backwards (arm and leg) and poles facing up (elbow and knee)
--- (can follow this: https://medium.com/@agm1984/how-to-rig-a-character-model-for-three-js-in-blender-846e258a9d9d)
--- TURN OFF their deform property
--- Can change the looks of the bone at Bones > Viewport Display > Custom Shape
--- In Pose Mode... select the IK and then last child of limb, and then Shift+I to switch on the IK.  Set the chain length (important) IK at bone constraints tab, else it will pull till the root.  For humans, last child should be at the wrist and chain length is 2
--- The same IK panel, select Target Pole > Armature > the pole bone.  If the bends are pointing a different direction, go back to the IK section and change pole angle to 90 degrees or whatever fits!
> May also want to do one IK for the head?
> Do mirroring where necessary (preferably using w > symmetrize, provided .L bonenames are used)
> Create root mover bone between feet pointing front.  The spine and all 8 IK bones are parented to it (detached/keep offset)
> Entire Skeleton done here.
        Root Mover  ─┬
                     ├─ IK's 
                     ├─ Poles
                     └─ Spine   ─┬
                                 ├─ Other bones
> Parent mesh to armature (empty vertex groups for mechanical stuff and auto weights for organic) BUT FIRST, remember to uncheck Deform for the root and controller IK bones!
> Renaming bones should affect vertex groups as long as mesh connected through armature modifier
> Mechanical object: select and click assign weight (L for selecting linked vertices)
> For organic object, automatic weights should be created.  Just need to paint (mirror painting?)
> To pose a bone chain at once, select the bones in the chain and click individual origin (?)
> Hiding bones: actually not hidable, just moving them to a different layer.  In Pose mode, select the bone and press M and click the layer
> To pose, just adjust/move the different controllers (hands, feet, elbows, knees, entire body, spine)
Alternate rig: https://medium.com/@agm1984/how-to-rig-a-character-model-for-three-js-in-blender-846e258a9d9d

____ Tutplus Workflow ____
https://cgi.tutsplus.com/tutorials/building-a-basic-low-poly-character-rig-in-blender--cg-16955

____ Adding Props to bones (like Poser) ____
> Prop model must be positioned exactly as how it would rest on the default pose
> Click on a prop and add a constraint > Child Of > Select Armature > Select Bone > Set Inverse

____ Conforming Clothes ____
> Based on https://www.youtube.com/watch?v=WVfTRwXpmuQ
> Clothes must be modeled based on character's default pose
> Position it over the rigged character nicely
> Parent it to the armature with empty vertices
> Select main mesh and then select new clothes
> Go to Weight Paint mode
> Scroll down and click Transfer Weights (All, Nearest Face, All)
> If it doesn't work, can try data transfer https://stackoverflow.com/questions/34719718/transferring-rig-weights-from-one-mesh-to-another-in-blender-2-76
> Another way is just to use auto weights on the same freakin armature
> To keep some skin from poking out, may need to
--- subdivide more (or subdivision modifier simple setting...
--- and add shrinkwrap modifier (with offset, nearest surface point, above surface setting!),
--- or manual weight-painting (tedious).
--- Seems that there is no way to hide inner skin polys
--- baked clothes-skin characters are still the best, it seems

____ Blender Object Control ____
> Control the location and rotation of stuff: Right side menu (N), There's Item and 3D Cursor, etc
> Each object has an origin (orange dot).  To set it, use Ctrl+Alt+Shift+C (or Search for Set origin, or W, O) and select an option (Origin to Center of Mass, etc).  
> So it doesn't need to be in the center of the world?
> A Blend file can contain many objects.  Each object is grouped under "Collection", and when linking, the collection is selected.
> It's like Layout + Modeler, but combined into blend files.
> Merge meshes using Ctrl+J (join)
> Mirror Vertext Group:  Copy existing group, RClick > Mirror Vertex Group

____ Blender Texture Paint ____
> Blank model needs to be unwrapped, maybe using Smart UV project (add island margin 0.1)
> Click Texture Paint Mode.
> Left side Image > New.  You should get something black. (No need, if you set things up in the nodes first.  Multiple alpha png stacked textures: see [TRANS])  To create a new alpha image, click new, click the color and rgba (can adjust the alpha there)
> Right side, in texture tab, create new Brush. (don't create if you just want a solid color)
> Right side tools options part, lots of adjustments, after clicking on the brush tool, let's say.
> If you start painting but nothing happens, maybe the correct Texture slot is not selected
> To draw straight lines, click line in Stroke options.
> To adjust brush size quickly, press F.
> To adjust brush strength quickly, press Shift+F
> Stencil (Image overlay) : Texture tab brush section, click new and select the image.  Tools panel texture drop down, select stencil.  Right click drag to position.  RClick+Control to rotate.  Rclick+Shift to zoom!
> Eyedropper: point to a part and press S.
> Fill: not possible.  This crap tool fills selected faces instead of what you draw...
> Erase: set Blend mode to Erase Alpha
> Symmetry paint is possible

____ Blender Normal Map Texture Paint ____
> Difficult.  Need to bake it, bla bla bla.  3D Coat is a lot better.
> It can paint bumps instead.
> Alternative: Sculpt and bake the normals!  See sculpting section.

____ Blender Subdivision modeling (good, it seems) ____
> Control loops round the geometry (main)
> Support loops determine rounding value.  Mostly using Ctrl+R (loop cut) and Ctrl+B on edges (bevel)
> Support loops 2nd way to create (primary way?): Ctrl+B bevel, pressing P to move the inner part out...
> Creases create very sharp edges (modifier use creases must be checked. no need support loops): Shift+E.  Undo crease by setting N panel Edge data crease value 0.
> Frequently-used techniques:
--- Ctrl+2 for edge selection
--- Alt+RClick for loop selection
--- Ctrl+Shift+RClick for whole face selection
--- Ctrl+R to loop cut (most effective, spam it to "tighten corners")
--- Shift+E on edges for sharp crease (modifier use creases must be checked. no need support loops extra polys)
--- Ctrl+B bevel, pressing P to move
--- E, S also works (extend and scale) but the corners are diagonal, so the subdiv corners become rounded
--- sliding selected loops/edges (press G twice)

____ Blender Grid Fill modeling (good for parts of clothes like pockets, collars, etc BUT...) ____
> NOTE: superseded by subdivision + creases?
> Must have a looped edge of even number vertices.  If not, pick an edge and subdivide one.
--- start with a plane, divide it into a grid.  Delete the inner vertices, adjust the 4 edges to desired shape
> Then do Grid Fill (search)
> F6 to adjust controls
> Flip normals where necessary
> Use sculpt mode to smooth edges

____ Blender Sculpting (easy, but not good for precision.  good for organic) ____
> To sculpt stuff:
--- even with low poly model, just go to sculpting mode or click sculpting workspace.
--- click and drag to make changes.  Ctrl+Click will do reverse sculpt (pull out becomes push in).
--- in the Tools panel (n), look for Dynatopo, as it will add new polys to your low poly stuff.
--- like Texture paint, there's stroke options, F and shift F for resizing.
--- Symmetry tab lets you do changes to both sides
--- Using texture (insert a black bg and white fg image) and anchor stroke allows you to sculpt textures.
--- Using stencil (like texture paint)
> Baking Normal map: From StackExchange: https://blender.stackexchange.com/questions/2466/how-does-normal-baking-work 
    and https://www.youtube.com/watch?v=0r-cGjVKvGw
--- Retopologize the sculpt (Blender decimate tool)
--- Unwrap the low-res mesh
--- Create a new Material for it (the lores one)
--- In the lores Material node editor, create a new Image Texture node with color space NON-COLOR (IMPORTANT!)
--- Create a new image there. I recommend enabling 32-bit Float to prevent any banding or other image artifacts.  Make sure it is selected (orange border)
--- Place the 2 objects on top of each other (if they aren't already)
--- Select the high-res, then the low-res mesh
--- Tab into Edit Mode of the low-res mesh, select everything
--- in short: select target image texture in node editor, select hires object, lores object, all faces of lores (4 things)
--- Go to Render tab (camera icon), use Cycles render.
--- In the bake panel, choose Normals for the bake mode and enable Selected to Active, ray distance set higher to bake details further out
--- Hit the magic bake button (keep an image editor window open to see how it goes.  Rebake by adjusting ray distance appropriately.)·
--- When it's done, remember to save the image as an EXR or a 32-bit format, otherwise some of the information in the normal map will be lost and you'll get obviously visible banding.
--- Plugging in normal map: in Shader nodes, an image texture node loads the normal map (with color space NON-COLOR -IMPORTANT!), color linked to a normal map node, and the normal linked to BSDF normal.  (2 extra nodes)

____ Blender Sky 2 ____
> Newer method from Blender Sky 1
> Just plug in the Environment Texture node and load an hdri equirectangular image (.hdr file where each pixel can store more than 0-255, get from hdrhaven site).  The whole scene will be lit by any lights from the image.  So if there is a sun spot, that's the lighting source.  To change direction, rotate it using Texture Coordinate node generated -> Mapping Node Vector, Vector -> Environment Texture node.  Then adjust rotation Z!
> Adjust brightness using the background node strength slider.
> Note: USING JPG or PNG or gradient!  The lighting will be shit.  But inserting a sun light solves the problem.  Make it bright (strength 10, etc).  Kinda looks better than hdri from initial tests!

____ Blender Sky 1 ____
> Color the world appropriately (see worldsky_nodes.jpg in skybox_configs folder) You can use color ramp... but if nothing shows up... set mapping node rotation y 90 degrees.  If it's too bright there are a few possibilities:
--- it must not have full ambient occlusion (world tab).  Ambient Occlusion requires nodes for adjustment to get good results. https://www.youtube.com/watch?v=lB7l_IUcQn4
--- there's an object material with non-black emission (emits light).  Turn it black and it should be ok
> Make a skybox which is a squashed dome.  4km x 4km x 1.4km (may need to set viewport and render distance clip limits!)
> Make a ground plane around 2km x 2km for the floor
> Texture it using the nodes to create clouds (see skydomeshader_nodes.JPG in skybox_configs folder)

____ Blender export panoramic backgrounds ____
> Resolution should be 2:1, preferably 4000x2000.
> Position camera parallel to ground, looking north, no roll rotation.
> Camera tab : Type Panoramic, Panorama Type equirectangular.
> Render tab color management section, may need to change Look to Very High Contrast.  And then background node strength 0.5

____ Blender Gotchas ____
> Wireframe on shade doesn't want to come off.  Object > View Display > Wireframe & All Edges.  Doesn't work?  Select it, go to Edit mode and go back (possibly bug)
> Pivot Point : check the part that says Global.  Should be next to it.
> Shift+N to make normals consistent if they screw up.
> Rotating in Perspective mode, changing the pivot origin... Select something and press Num .
> Save Settings as Default : File > Defaults > Save startup file