Hello I am new to houdini and currently trying to learn the basics in modeling and texturing and want to get a solid unterstanding of the software and the workflows.

Currently I am trying to texture an eye and cannot seem to wrap my head around on how to mix/overlay a radial gradiant with a noise map to get a nice looking distortion to make it look like a more realistic iris.

Any hints, advice or examples on how to go about this?…it would be greatly appreciated


So this is what I am trying to achieve

https://farm1.staticflickr.com/118/262102618_482d372830_z.jpg?zz=1 [farm1.staticflickr.com]

and this is currently my shop setup and what it looks like when I render. The new_gradient Node is a small asset with a radial color gradiant.

Your description wasn't entirely clear, nor were the images; generally posting a houdini file along with your question is the best way to get an answer.

For texturing an irirs, the easiest way is to just map a photograph of an iris onto the eye, but I'm assuming this is a learning exercise rather than a final render project.

The next easiest way is to generate radial uv's using a polar projection, and use a uvcoords vop to drive the pos of your noise.

If I read your description right, if you've created a procedural radial ramp, it should be essentially the same thing, just connect the ramp to the pos of your noise.

I've created examples for the 2nd and 3rd options, it might give clues for debugging your setup.

Yes I am sorry if I wasn't able to clearly say what I am trying to do. But it is pretty much what you uploaded.

I was trying to avoid photoshop and trying to do everything in Houdini to get some exercise like you said. But looking at your setup I would have never figured that out haha. Thank you very much, I will try to recreate and learn from it.

I found this on the forums:

https://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=74177 [sidefx.com]

and tried to adjust it to my purposes but it just didn't give me the results I was looking for. It distorts the UVs Scale but it just looks messy.

You can see the best I could get out of this setup, below.


If I just connect the ramp to the pos of the noise it distorts the noise in a radial kind of way not towards the center like in your examples.

It looks like the Screenshot at the very bottom

can you save that file again with your ramp hda embedded?