Primuv of Point

[unshmettr]

Hi! How can I extract the primitveuv of given point  on a curve (I asume that on polys one point is used by multiple primitives). Like the one xyzdist provides?

[konstantin magnus]

Hi Joe,

you could simply set the xyzdist()-function to the first input, so it's searching on its own geometry stream:

int prim;
vector uvw;
xyzdist(0, v@P, prim, uvw);

v@uvw = uvw;

Alternatively, the resample node can output the "curveu" attribute. Just make sure to disable "maximum segment length" to avoid any changes on the curve.

Edited June 10, 2022 by konstantin magnus

[unshmettr]

Thanks konstantin, thanks! Just concerned about what happens when multiple curves overlap. I hoped that this can be extracted from some kind of primitive intrinsic or any other way that does not involve a point/prim lookup.

[konstantin magnus]

I am afraid there are no intrinsics for points or vertices. But connaiseurs may divide the vertex index by the number of vertices on each primitive:

f@u = vertexprimindex(0, i@vtxnum) / (primvertexcount(0, i@primnum) - 1.0);

 

[unshmettr]

Yess, that's amazing. It's in my test it was 8x faster than the resample sop. I've had some weird thinks happening with the resample sop, that's why I was looking for alternatives.