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Technical Discussion » point transform to worldspace
- AndyW
- 336 posts
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I'm a little stumped on getting worldspace transforms from a rivet, for purposes of driving a Vellum sim. I'm importing FBX animation and using Rivet to get a point group for transforms, I need to set my initial transform to that group as a parent, and then run the sim based on that point motion. Any advice on this is much appreciates
Technical Discussion » Crowds - Link agent layers to states
- AndyW
- 336 posts
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I've gone through those videos and they're very helpful. To be more specific agent layering is working just fine for me, but I'm looking for a way to weight certain layers to 0 based on the agent state. I've heard of people doing this with regex but haven't seen any specific examples on how to go about it
Technical Discussion » Crowds - Link agent layers to states
- AndyW
- 336 posts
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I'm curious how people are going about this. I'd like to be able to link specific agent layers to to that agent's current state/clip. I'm not transitioning between states so that's not a concern. If I have an agent with a list of states and I want to for instance, only have sword layers in the hands of agents using the swing-a-sword state, how would I go about that? Thanks!
Technical Discussion » VEX find points at branching areas
- AndyW
- 336 posts
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Technical Discussion » VEX find points at branching areas
- AndyW
- 336 posts
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I'd like to group points in an l-system only at branches, in other words, find points that are connected to more than two polylines. Any ideas how I would go about that in VEX?
Technical Discussion » How to random scatter seed for multiple copies
- AndyW
- 336 posts
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Stamp expressions only work on the copy input side, not on the template points as far as I know. Why not duplicate before scatter? You'll always get a different point distribution
Technical Discussion » How to random scatter seed for multiple copies
- AndyW
- 336 posts
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I like to set attributes on the points themselves and reference those in the copy stamp, it's easier to troubleshoot than writing expressions right into the stamp slots. I hope the attached file is helpful
Technical Discussion » How to random scatter seed for multiple copies
- AndyW
- 336 posts
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It's not very clear what you're trying achieve, changing the global seed on the scatter nodes just changes the distribution of the points you're copying to
Technical Discussion » Randomly remove points from group over time
- AndyW
- 336 posts
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For that group do in a wrangle:
if(rand(@ptnum)<ch('threshold')){
removepoint(0, @ptnum);
}
keyframe the threshold slider over time
if(rand(@ptnum)<ch('threshold')){
removepoint(0, @ptnum);
}
keyframe the threshold slider over time
Technical Discussion » VDB remove interior
- AndyW
- 336 posts
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Technical Discussion » VDB remove interior
- AndyW
- 336 posts
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I actually figured out a brute force method: Convert to poly, convert back to VDB and then convert to poly once again. Interior prims are culled because the VDB conversion only looks at airtight geometry, at least that's what I think is going on. Either way, it works like a charm.
Technical Discussion » VDB remove interior
- AndyW
- 336 posts
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because of the way I'm combining VDB volumes, on conversion I'm getting a lot of polygons on the inside of the mesh, I'm sure there's a way to remove interior voxel data based on a threshold, I'm just not sure exactly how to go about it, tips?
Technical Discussion » FLIP sim add gravity only to detached particles
- AndyW
- 336 posts
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I'm looking for ideas on how I might mask gravity just to smaller droplets in a FLIP sim, that have detached from the main sim? Tips?
Technical Discussion » primitive groups and packed prims
- AndyW
- 336 posts
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Interesting, that seems counter-intuitive. I wonder in what situations you would want to transfer groups when packing…
Technical Discussion » Scatter Points only on Polygons which are facing upwards
- AndyW
- 336 posts
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Turn on with a Group SOP turn on Keep By Normals and set your angle and spread threshold, scatter to that group
Technical Discussion » primitive groups and packed prims
- AndyW
- 336 posts
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I'm confused why my prim groups get screwed up after assembling to packed primitives, I need to delete the inside groups of my fractured geometry after RBD sim. In the enclosed file I'm coloring the inside prim groups before and after they're converted to packed prims, what am I missing? thanks!
Technical Discussion » Cellular infection growth a la Entagma
- AndyW
- 336 posts
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Thanks, that's the ticket. My implementation isn't the greatest at the moment but it does seem to work, here's an example file
Technical Discussion » Cellular infection growth a la Entagma
- AndyW
- 336 posts
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Ok so put another way, I need to find the vector between the current point and it's neighbor, and weight the ‘infect’ attribute in a certain direction. I've enclosing a simplified infection solver set up with a more compact algorithm
Technical Discussion » Cellular infection growth a la Entagma
- AndyW
- 336 posts
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I've been working with growth solvers using nearpoints() with some initial setups demonstrated by the brilliant folks at Entagma. However I'm getting a little stumped when I try to weight the growth in a certain direction. In other words, I'd like like the solver to find nearest points only in the +x direction of the currently infected points. Pointers? Ideas? Thanks!
Solver code:
float radius = 0.075;
int nbrs = nearpoints(0, “infected”, @P, radius);
int cnt = 0;
float accum = 0;
foreach(int nbr; nbrs){
float infection = point(0, “infect”, nbr);
float dist = length(@P - point(0, “P”, nbr));
float weight = 1 - smooth(0, radius, dist);
accum += infection * @Cd.r;
vector nodepos = point(0, “P”, nbr);
v@dir = normalize(nodepos - @P);
cnt++;
}
f@infect = f@infect + accum/float(cnt);
Solver code:
float radius = 0.075;
int nbrs = nearpoints(0, “infected”, @P, radius);
int cnt = 0;
float accum = 0;
foreach(int nbr; nbrs){
float infection = point(0, “infect”, nbr);
float dist = length(@P - point(0, “P”, nbr));
float weight = 1 - smooth(0, radius, dist);
accum += infection * @Cd.r;
vector nodepos = point(0, “P”, nbr);
v@dir = normalize(nodepos - @P);
cnt++;
}
f@infect = f@infect + accum/float(cnt);
Technical Discussion » Vellum collision - what am I doing wrong?
- AndyW
- 336 posts
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