Mocap

Coding Python Support
1

Has anyone here ever monitered encoder clicks directly to Blender VIA Python.

I have this idea that I am dying to try, that involves getting the current position of two encoders and solving for Z.

I have the encoders (Linear Sony Magnascales), or mouse parts.
I have an “Optitracker” PCI board to make my interface and the C source code for it.

I have the construction of the mechanism that I am planning well along on the (probably mis-guided) assumpion that I can make this work.

I know Blender and have a smattering of Python.

Where would I start looking for a way to make this connection? Whats my Python strategy?

2

There’s an easy way and a hard way of couse :slight_smile:

The easy way:

  1. Using your C code, dump the sensor information to a text file.
  2. Load and interpret the data from python in Blender.

Or the hard way:

  1. Wrap a python interface around your C code.
  2. Load the python module from within Blender.

Good luck!

3

Hmmm. the easy way sounds to me like it would have some latency issues.
So let me ask some stupid questions until I catch up with the reality of the second method.

  1. Wrap a python interface around your C code.

Could you give me a simple example to illustrate this sort of thing.

  1. Load the python module from within Blender.

So I would be compiling my own module in C and calling it like I might call the Math or Draw module?

I have had a couple of false starts in my understanding of calling outside modules. Where sould I be reading/studying to round out that area of my python ability???

4

With the first method, it would be offline, ie you record your mocap data, then load it into Blender. I would try this way first, you should be able to reuse all the Blender-python bits.

To create your own module, you can try:
http://www.python.org to do it by hand,
Extending & Embedding Python (the reference) http://www.python.org/doc/current/ext/ext.html
http://swig.sf.net for an automatic tool.

Example code would be from the Blender source, or:
http://www.python.org/doc/current/ext/simpleExample.html

Good luck!

5

I think that may be what I needed to put me on the trail. Thanks Alien-xmp

6

This project is a really cool idea. You should make a website with some picture and more information. asdf_46

7

Thanks asdf_46:

I think that there are some broad implications for the scripts, but I am out of my depth in moving this along in any kind of timley fashion.

I will let you in on part of what what I am doing tho.

I am building two new machine tools in my studio this year.

The first is a tracker that has a cutter that I can push around manually in the X&Y axis’ and has a motion control assy that positions the cutter in Z, for carving the soundboards for the string Basses and archtop guitars that I build.

http://www.door3.org/tracker.gif

The second is a much more ambitious project that will the my third generation of 3 axis CNC profiler, designed specifically for shaping stone for sculpture. I can do Blender models and meshes in most machinable materials now, but it is a cumbersom processthat needs LOTS of manual input from Maya and Surfcam. If I can work out the passing of these values through the port (serial, USB I dunno) I can machine directly from Blender/Python, and thats why I am here.