Hello,

i’m trying to make some particles appear on a sphere with a texture.

That works, i use Volume Select on the sphere, and tell it to select the faces by texture map (noise with white and black values). The problem is, i want that when the map turns black it would delete all particles in black areas.

i’d like to use a delete operator with delete selected, but I don’t know how to select the particles by a map or mesh faces,

any help would be much apreciated!

Using the volume select on your object isn’t necessary. You can use the density by material in the position object operator to get the particles to be born based on the texture map of the position object.

If these particles are static, you could do this:

-Clone the object you’re using in the position object op and make a copy of the material on it.
-Clear the diffuse map of the copied material, put in a color correction map and check invert.
-Copy the diffuse map from the original material and paste instance it into the color correction’s map slot of the copied material.
-Assign the copied material to the copied object.
-Now you have the original object with the original texture and a copy with the inverted texture.
-In pflow, use a speed by surface op with the copied object as the geometry, set it to control speed continuously and check speed by material.
-Add a speed test after the speed by surface op and set the test value to something low like 1.
-Wire the speed test to an event with a delete op in it.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC