A Grid SOP.
A source of noise (Noise TOP, TOP to CHOP, a shuffle and a Math CHOP to put everything from 0,1 to -1,1)

I take coordinates with the SOP to CHOP from the Grid SOP. and I combine that with my noise using a Math CHOP that acts a bit as a dry wet, multiplying the noise influence before going to SOP rendering.
The process is easy to understand for me… until the next part.

The distortion occurs well etc BUT when I stop the influence of noise by putting my Math CHOP to zero, I don’t have the same rendering as the initial grid.

I know it is a question of vertices order… but what did I do wrong there?

Would someone help me to go out of my error here ?
I’m stuck.

I think it is more related to vertices sorting than this.
Actually my res is 32bit float RGB (don’t need alpha here)

But I don’t know why I should re shuffle or order that as I don’t feel my light network reordering initial grid vertices…
I miss something, and I love that because I’ll learn something nice after this one

I didn’t fully understand what goal you have in mind, but my guess is you should wire the grid SOP into the blue CHOP to SOP. That preserves the primitives but allows you to replace the positions with a CHOP, your math2 node.

I understand what you mean but I don’t understand why this network change something in the vertices order.

For instance, my grid => soptochop gives me initial coordinates.
Then, I add (with the math2 CHOP) values to the initial coordinates according to math_influence, which is “just” a multiplier. So basically, if I set this latter to multiply by 0., my math2 should do the following operation: initial coordinates + 0 (all vectors… I know)
but my chopto SOP after math2 CHOP shows vertices order which have been changed.

Hi David, I got it.
Actually, I thought the SOP to CHOP was taking EVERYTHING (x,y,z vertices and all attributes required for drawing), but as far as I understand, it takes “only” x,y,z (as I checked the box for that).

I don’t understand what’s going from the Grid SOP to SOP to CHOP when we wire them together.

I think I’m touching here something important in my TD learning about SOP