Flow maps?

[kremiansky]

Hi there, I know in some real time engines you can paint Red ad Green maps to direct looping flow of textures, is there something that can be achieve a similar result in Vray for Maya?
Thanks!

[dgruwier]

It's complicated, but it is, and it's not even a VRay thing, just a Maya thing, so you can preview it directly in the viewport.

When you add a file node or ramp or something else that comes with a place2DTexture, the place2DTexture node as an "Out U" and a "Out V", and the file node will have corresponding "U coord" and "V coord" input. Those are just values from 0 to 1, they're like the red and green channels of a UV flow map. So just add your flow map as a file node (with its own default place2DTexture node untouched), and pipe the Out Color R and Out Color G from that file node into the "U coord" and "V coord" on the texture you want to distort. To animate the offset, just create a plusMinusAverage node in between. Whatever you add to it will be the offset, and you can animate that value.
I'm fairly sure that should give you the same result as a UV flow map would in a game engine, but I can't do a comparison so I'm not entirely sure.

You can go a step further and create the flow map inside Maya:
If you create two ramp nodes, make one a "V Ramp" that goes from black to pure green and the other a "U ramp" that goes from black to pure red, and then add those two ramps together with a plusMinusAverage node, you'll get an image like this, which should look familiar. Now just connect it with the texture you want to distort like before, and it'll map as if it had a regular place2DTexture node on it. But now, if you add noises or otherwise modify the output of the two ramps, you can create some cool distorting and twisting effects. My favorite is to distort one noise texture with another, it creates some really cool organic looks.

Hope all of that made sense. Unfortunately I can't give you an example file, but let me know if you have trouble getting it to work.

[kremiansky]

It's complicated, but it is, an it's no even a VRay thing, just a Maya thing, so you can preview it directly in the viewport.

When you add a file node or ramp or something else that comes with a place2DTexture, the place2DTexture node as an "Out U" and a "Out V", and the file node will have corresponding "U coord" and "V coord" input. Those are just values from 0 to 1, they're like the red and green channels of a UV flow map. So just add your flow map as a file node (with its own default place2DTexture node untouched), and pipe the Out Color R and Out Color G from that file node into the "U coord" and "V coord" on the texture you want to distort. To animate the offset, just create a plusMinusAverage node in between. Whatever you add to it will be the offset, and you can animate that value.
I'm fairly sure that should give you the same result as a UV flow map would in a game engine, but I can't do a comparison so I'm not entirely sure.

You can go a step further and create the flow map inside Maya:
If you create two ramp nodes, make one a "V Ramp" that goes from black to pure green and the other a "U ramp" that goes from black to pure red, and then add those two ramps together with a plusMinusAverage node, you'll get an image like this, which should look familiar. Now just connect it with the texture you want to distort like before, and it'll map as if it had a regular place2DTexture node on it. But now, if you add noises or otherwise modify the output of the two ramps, you can create some cool distorting and twisting effects. My favorite is to distort one noise texture with another, it creates some really cool organic looks.

Hope all of that made sense. Unfortunately I can't give you an example file, but let me know if you have trouble getting it to work.

Perfect, many many thanks! I will take a look into that now!