random offset in triplanar

V-Ray V-Ray for Houdini General
1

Hi I have a fractured geometry with a bunch of pieces. I want to apply a triplanar material with random offset per piece. However there is no offset input for the vray triplanar node like in other render engines where I can plug an ID or something. I see that there is a random mode for User attribute. However I am unable to get that to work at all. Is there a solution in Vray to do this? thanks

2

Hi Adrian,

The Triplanar node has the option to make random offsets built into it, and those can be driven by a custom attribute if necessary.

triplanar.png
triplanar.png835×599 36.4 KB

Check the type of randomization that you need and then you can set the “Random Mode” to “user attribute”.

Best,
David.

3

Thanks! David. Do you think you can make a sample of it working? Ive tried the custom user attribute and cant get it to work at all. It works in Arnold, but im not sure what im doing wrong in Vray.

4

In Arnold you simply set it up like this plugging in a user ID attribute into a random going into the offset input of a triplanar node. However I need to do it in vray.

arnold random offset by ID.PNG
arnold random offset by ID.PNG491×315 13.7 KB

5

Hi again Adrian,

It appears (I tested in VFH 4.3 with latest stable build) that this is not working as expected like you just pointed out.

triplanar-issue.jpg
triplanar-issue.jpg1120×446 80 KB

@Gosho.Genchev , I think this was flagged as being an issue with the triplanar some time ago but I think it was forgotten or assumed to be fixed already, probably needs a look at.

Best,
David.

6

Thanks David for taking the time to try it out. Hopefully it will be fixed immediately, since now i’ll have to use Arnold and composite with the rest of my Vray scene making it much more difficult.

7

Hey, is it a lot of offsets that you are trying to get? If you’re ok with just a few, you could at least for now use a multi I’d texture that cycles through different triplanar projections that have different offsets

Alternatively you could also try 2 more approaches (this is just from the top of my mind, could test it out tomorrow);
- use the attribute to offset the U or V coordinates in the image bode (this needs to be tested for when the model has no uvs).
-i noticed that the projection node has a triplanar mode, so in theory we could just offset the “uvw” data/output with a simple math operation using your attribute.

Best,
David.

8

I have about 100 pieces. I just don’t want the texture to look the same on all the pieces, or like the texture is just slapped over all the pieces. I want an offset per piece, so it looks randomized… Thanks! i’ll look into those approaches and see if I can make any of them work.

9

Plugging in my user ID attribute into a random, and then into the offset u, and offset v of the image file seems to work okay for what I need. Thanks

uv triplanar randomization.PNG
uv triplanar randomization.PNG855×501 37.4 KB

10

Awesome :smile: