Tyflow "density by texture" wont work with noise map + VrayMtl

V-Ray V-Ray GPU Issues
1

Hi all,
with TyFlow I want to control particle’s density with a procedural noise.

So I created a ’ VRaymtl 'using noise map as diffuse.
A plane with a ‘UVW map’.
And a Tyflow with ‘position object’ node set on ‘density by texture’.

It works but the particles are not positioned exactly on the noise rendered.
They follow a noise but not exactly the same.
It’s shifted or distorted but the 2 noises are not similar.

It works well with a gradient or a bitmap but not with the noise.
I tested with a standard material + scanline render and it works so I guess it’s linked to the VrayMtl…I’ve posted this on TyFlow forum too…

(Max 2025 + VRay GPU 6 update 2.1 + TyFlow 1.114)​

pos by texture.jpg
pos by texture.jpg1298×385 89.8 KB

tyflow map positioning.rar (44.5 KB)

2

In this specific situation, if you swap the mapping to ‘world xyz’ then you’ll get what you want.

EDIT: Actually I just saw you’re using gpu, which doesn’t work. GPU does noise differently and I don’t recall if there’s a fix for that.
CPU will work with explicit too, though you need to ‘use real world map size’.

EDIT 2: Well it seems that it’ll work just fine with GPU if you use Bercon noise, so that’s an option :slight_smile:
Make sure it’s real word explicit in the Bercon settings as well as the plane.

3

Thanks a lot for answering, I switch from Vray GPU to Vray and it works :stuck_out_tongue:

4

FYI: Logged the issue (internal bug-tracker id: VGPU-6578 ).