3D App Creation - A learning exercise

 Learning exercise - making a 3d app of some sort. Not sure what sort. c++ and python combo.

 

So far I've learnt about:
PyOpenGL = http://pyopengl.sourceforge.net/documentation/
GLFW = https://www.glfw.org/docs/latest/build_guide.html
vcpkg = automate dependency setup for GLFW and other libraries
vcpkg and CMake = https://vcpkg.io/en/getting-started.html
CMake Script FindGLFW3.cmake = https://cmake.org/cmake/help/latest/command/find_package.html
Wavefront OBJ = Details https://en.wikipedia.org/wiki/Wavefront_.obj_file
Lighting & Materials- OpenGL = https://learnopengl.com/Lighting/Basic-Lighting
Transformations - OpenGL = https://learnopengl.com/Getting-started/Transformations
Triangle Normal Calculation in OpenGL = https://learnopengl.com/Lighting/Basic-Lighting
OBJ Preprocessing for Compatibility = https://github.com/pywavefront/PyWavefront

Hardest part to solve - Exploding Vertices after obj import

Face Def / Quad Handling -
- OBJ files contain non-standard face definitions + use quads .
- Needed to convert quads to triangles = face definitions standardized.
- Had to remove unnecessary lines \ smoothing groups - simplify parsing.
Vertex Normalization -
- Needed to sort incorrect scaling or positioning due to varying coordinate extents = calculate (normalize) the center and maximum extent of the model
- needed to reposition and scaling vertices to fit within a view.
Missing Vertices -
- needed to use checks to skip invalid data = avoid crashing
Incomplete Triangles -
- The `pywavefront` library was, on my first attempt, returning only partial vertex data.
- Had to force triangles to adhered to a set length - for example the common graphics issue - avoiding malformed geometry.

learning exercise – animating explosions / projectiles with code and physics

Velocity: v0=v×(1+random.uniform(−rv,rv))v0=v×(1+random.uniform(−rv,rv))

Mass: mass=m×(1+random.uniform(−rm,rm))mass=m×(1+random.uniform(−rm,rm))

Launch Angle: random.uniform(0,360)random_angle=random.uniform(0,360)

Mess with time (bit slow to process but things look bad if not slowed down for aesthetics):

Δt=0.1speed_factor×(1+random.uniform(−time_randomize_bias,time_randomize_bias))Δt=speed_factor0.1×(1+random.uniform(−time_randomize_bias,time_randomize_bias))

Bias Launch Direction:.

angle_variation=(1−direction_bias)×90angle_variation=(1−direction_bias)×90 and

random_angle=random.uniform(launch_angle−angle_variation,launch_angle+angle_variation)random_angle=random.uniform(launch_angle−angle_variation,launch_angle+angle_variation).

Air Resistance: (1−air_resistance×Δt (delta t) /randomized_mass)

Blender testing – any 3d program really - :

Refs:

Randomize:

https://en.wikipedia.org/wiki/Monte_Carlo_method

Hyperphysics:

http://hyperphysics.phy-astr.gsu.edu/hbase/hortraj.html

http://hyperphysics.phy-astr.gsu.edu/hbase/trajs.html

http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html

https://physics.info/projectiles/

khan:

https://www.khanacademy.org/.../v/projectile-motion-part-1

Misc:

ΔT (Delta T)

https://en.wikipedia.org/wiki/%CE%94T_(timekeeping)

WIP - Blender Rigging Framework

 WIP - Blender Rigging Framework

Blender Auto-Rig Add-on

A test for a  Blender Add-on I've been working on in what spare time I have. I've written most of the functions and classes I need to build any rig or animation tool. The fun part is being creative with them.  Early days. 

Python Learning in Blender- Sine expression to Drive Bone Rotation

A quick python learning exercise in blender:

1. Scripted various controls with arguments for names/limits/shape etc
2. Scripted a bone chain definition with arguments for names/numberOfBones/transformPlacement/axis/O.O.R etc
3. Created a script to iterated through the bones and deliver a sine expression using the controllers Y transform as input variables for the bones XYZ rotations - sin(frame*"freq+...etc")

Links:

• Sine Expression implementation: https://en.wikipedia.org/wiki/Sine_wave
• Bone iteration for expression delivery: https://blenderartists.org/t/iterate-through-bones-of-armature/667942
•  Driver delivery: https://blender.stackexchange.com/questions/13747/pose-bone-drivers-through- 

Now - the expression needs a little work (ie: clamp(#,#,#) etc), before I can expand upon it.

Blender Add-on no:1 - Texture Set Manager

I wanted a quick way to load, name and update texture sets based on selected objects so I coded this in Blender.

...as well as in Maya and Max.

I'm finding it useful for quickly flicking through textures in dense scenes and for keeping all texture sets named and organized.   

Here is a flat shaded viewport screen grab of my text scene:

Render test:

 I can switch between image types( jpg,tif,png ), sizes( SM,MD,LG ) and image sets( type of 
wood, skin, metal... etc ).  

The process of making add-ons in blender is a relatively fast and simple one:

Python Notes - Misc 01 - Blender/Maya

Experiments in creating organic shapes from particle motion and curves

1. Particle set up for testing

2. Turn these particles into curves. There are two ways to do this.

The first way involves expressions which allow the curves to be draw in real time. 3D Splanchnic has a tutorial showing what to put where. Watch it HERE.
code for expressions:

(update: if ( frame%10 == 0)  is simpler)

The second is a script. Bryan Woodward’s 'ParticletoTube' Script for Maya makes tubes out of particles by first creating curves. The first part of the script loops through the timeline frames for "theParticle" and then uses a nested loop to capture each "particlesPosition" and draws each curve form the "pointList". Read about the script HERE:.

Code:


Now curves can be generated from the particle positions:




3. Finally a script is needed to turn these curves into organic looking geometry. Andrew Tubelli has a nice script for doing just that. Download it from his site HERE. The code simplifies what would be an annoying task by adding a UI with a few friendly sliders:


Completing the process via the Maya UI instead of the script:


The code rebuilds the curves based on "arcLen", creates nParticles for the curves and evaluates a mel command to create polygons with the ability to set attributes Via a UI.

Note: Some variable Changes are occasionally needed. For example the  curves generated by particles can be excessive - Try changing the (arcLen)*5 to say (arcLen)/5 or adding it into the UI.

I also needed to up the '.maxTriangleResolution' count.

Example:

4. A few shapes generated by moving a  passive collider around so as to alter the particle motion..

 

5. Now an experiment just from wires. I used a skull I previously modeled to draw curves on and then turned the curves into geometry.

 

Preiew render experiment

Some paint effect brushes added: