Shaders - what's going wrong here?

[Aunty Betty]

Hi I'd be grateful for any help.
I'm roughing out a compositional sketch and have placed a snow shader on a poly object which has been smoothed at render stage to 3.

Why is the snow shader looking so damned weird?

Regards

[Patrick210]

Hard to say from this, why don't you post a screenshot of your shader tree.

[Aunty Betty]

It's the default snow shader in C5's nature section of the browser applied to an imported object ?

[Aunty Betty]

here's the file with the object in question.

[Nichod]

I'm not able to look at the file at the moment. But three possibilities that I can think of are:

1.The poly object is a group of objects and the snow shader is applied to each of the objects individually and thus there is no flow (thus the odd artifact).

2.Another possibility is that the snow shader that comes with C5 is a texture map and you are seeing tiling.

3.Might also help to scale down the bump and color mixers procedural component (providing that there is one).

Any chance of seeing a screencap of the scene and of the shader tree?

[LoneGunman]

Just quick reply here, the file which is posted is not the same as the render above, please post the original file if you can, more help can be provided that way , file already posted renders fine on my computer (polygon mesh is bit strange, some polys are tesselated, some not ?)

I attached image with capture of modeling room, I applied smoothing to your mesh (is that what is couse of the problem ?) and as I said, it renders fine

[Aunty Betty]

Nichod, many thanks for taking a look at this problem.

here's a screen capture.

[Aunty Betty]

LoneGunman - here's the file with the snow shader added.
It's only this mesh that's causing problems. I had intended to create displacements for it later in Zbrush but have been stumped by why I'm getting this initial strange result.

C5 Mac

[Aunty Betty]

Nichod , seems you are right the bump noise size seems to have been creating this weird pixelizing effect.

Never seen this sort of thing before - mmmmm?

[LoneGunman]

Is it me or problem dissapiers when you apply box uv map (from within Carrara), did you maybe apply some sort of AutoUV feature in some other software, I noticed bump size thing too, wierd (!) ?

[LoneGunman]

I just tried again (uv mapping) but change was just so subtle, difference is small, i'll look at it tonite more, need to go to work now

[Aunty Betty]

LoneGuman - I used hexegon to create the mesh - and I'm fairly sure I never applied any auto uv feature but I just opened it in Lightwave and yes there is a strange uv mapping attached to it.

[kaga]

Hi, Aunty

I have downloaded your file. So, I propose changing the bump channel from "spots" to "noise".
The joints of the spots function are not smooth.
Try to set up snow shader to the Infinite Plane.
You will be able to see the joints.

And I think you must optimize the UV map by UV editor.

[Aunty Betty]

Kaga,
Many thanks for some great advice.

Regards

[Nichod]

Beat me to it Kaga I'd personally use Fractal noise though and play around with the scaling and density to get the right look. The default noise just isn't that clean to me, but that is a personal opinion.