transfer color texture to points

[MENOZ]

hello

i need to arrange some points on a sphere. they should exist only where my texture is white.

so i have my sphere with a black and white texture. i scatter some points on my sphere, then i want to delete the points wich fall on black areas of my sphere.

i can assign a texture to a sphere, and scatter points, but i don't know how to pass texture information to points.

can you help me please?

thank you

[aracid]

Hey

Try using the tex expression in a point sop, then a delete sop to prune the points u dont need.

float tex (string filename, float U, float V, string color_type)

Textures can be 1, 3 or 4 channel images containing 8-bit, 16-bit or floating point data.

tex("Mandril.pic", $BBX, $BBY, r)

in their example they use Bounding X and bounding Y to look up the texture,

you would probably need $MAPU $MAPV too lookup ur coordinates.

hope this helps

[old school]

Two easy ways. As aracid said with Point SOP but use $MAPU, $MAPV and $MAPW to return the uv's on the geometry, or use VOPs.

See the attached file for both examples.

map_color_to_geometry.hip

[MENOZ]

oh thank you very much!!

[rust3d]

Hey guys,

 

This is noob q. but is there a way i can get this to work without using the uvtexture sop?

Ive got a mesh with its own uvs...  and it seems it only works with the texture type @ orthographic.

 

I've been working in houdini for about a month so its prob something really basic that im missing. 

[dobin]

your uv should be point attribute...usually imported geometry from other apps come in with uv as a vertex attribute

all you need to do is to use attribPromote SOP and switch the uv from vertex to points

[rust3d]

    Cheers mate! works great now!!!!!