Messing with redshift a bit
Category Archives: Uncategorized
sop IK
I wanted to make a little IK node to use in sops to give things lots of legs.
Houdini 17.5 got a bunch of cool new vex functions like solveik() – these work like the agent solveik and agentsolvefbik and just process a joint chain and give you new angles. Pretty handy. http://www.sidefx.com/docs/houdini/vex/functions/solveik.html
reaction diffusion (again)
I took a old solver from about 6 years ago and finally updated it to opencl, so much faster
I didn’t bother to do a exact speed comparison, but its pretty substantial.
I then moved on to doing this in opencl on a 3D grid, not sure the implementation is correct but it generates some interesting results.
It took me a bit to change the 5 point stencil to a 7 point for the volume grid, I originally tried it with connected point grid but things got really weird trying to reuse the 2D versions code which is based on connected points
![](https://i0.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/animation.gif?resize=370%2C370)
![](https://i0.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/animation-1.gif?resize=370%2C370)
bootleg twee parser for houdini
I wanted to import a network of twee passages into Houdini to view as a connected graph
I used twee2 the command line tool to decompile twine2 gui html files
I the tw2 was a lot easier to strip apart in python.
![](https://i1.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/Screen-Shot-2019-05-07-at-8.32.28-PM.png?fit=584%2C502)
![](https://i0.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/Screen-Shot-2019-05-07-at-8.32.11-PM.png?resize=584%2C544)
![](https://i0.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/Screen-Shot-2019-05-07-at-8.36.47-PM.png?resize=584%2C428)
Just drop the code in a python sop and point it to the tw2 file, might work?
box packing 2D maps
I wanted a way to remove overlaps from some random rectangles.
![](https://i0.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/packing_boxes.gif?resize=540%2C540)
Here is the vex code – run once in a detail wrangle it loops a number of times over the points and pushes them outside while checking for overlaps
int relax_iter=chi("iter");
vector pp[];
for(int i=0;i<npoints(0);i++){
vector p1=point(0,"P",i);
push(pp,p1);
}
for(int q=0;q<relax_iter;q++){
vector newP={0,0,0};
int in=0;
for(int i=0;i<npoints(0);i++){
for(int j=0;j<npoints(0);j++){
vector min1 = pp[i]-point(0,"dimen",i);
vector max1 = pp[i]+point(0,"dimen",i);
vector p1 = pp[i];
float x1min = min1.x;
float x1max = max1.x;
float z1min = min1.z;
float z1max = max1.z;
vector min2 = pp[j]-point(0,"dimen",j);
vector max2 = pp[j]+point(0,"dimen",j);
vector p2 = pp[j];
float x2min = min2.x;
float x2max = max2.x;
float z2min = min2.z;
float z2max = max2.z;
newP = p1+rint(normalize(p1-p2)*4);
in = x1min <= x2max && x2min <= x1max && z1min <= z2max && z2min <= z1max? 1:0;
if(in){
pp[i]=newP;
}
}
}
}
for(int i=0;i<npoints(0);i++){
setpointattrib(0, "P", i, pp[i], "set");
}
![](https://i2.wp.com/www.natelapinski.com/wp-content/uploads/2019/05/packing_boxes-1.gif?fit=584%2C584)