Hey 3d people, New to VEX here.

The ampersand symbol means variable overwritten, right?
Then what does the uvw mean? UV coordinates? I've checked the intersection position on uv, but they weren't aligned


https://www.sidefx.com/docs/houdini/vex/functions/intersect.html [www.sidefx.com]

Correct!

bao007fei
Then what does the uvw mean? UV coordinates?

those are parametric UV coordinates within the primitive (or intrinsic primitive UVs), nothing to do with "uv" attribute

essentially primitive number + parametric uvw will define exact location within the primitive (e.g. on the polygon or within the tetrahedron)

many functions would return such location, intersect(), xyzdist(), uvdist(), Ray SOP, Scatter SOP, ...
then you can use such location in primuv() function (or within Attribute Interpolate SOP) to sample an interpolated attribute value at that location

tamte

bao007fei
Then what does the uvw mean? UV coordinates?

those are parametric UV coordinates within the primitive (or intrinsic primitive UVs), nothing to do with "uv" attribute

essentially primitive number + parametric uvw will define exact location within the primitive (e.g. on the polygon or within the tetrahedron)

many functions would return such location, intersect(), xyzdist(), uvdist(), Ray SOP, Scatter SOP, ...
then you can use such location in primuv() function (or within Attribute Interpolate SOP) to sample an interpolated attribute value at that location

Thanks for the explanation. I did some research and finally figured out what you mean about the Primitive Parametric Spaces. Much appreciate.