Hey Folks, Ive been experiencing problems when animating with displacement layers. It basically cuts up into huge artefacts in close range shots. I know there are a few things I can do…like pump up the shading quality in the objects parameter, and reduce the actual bump parameter so it isnt so drastic. But the effect in still images is just what I want. I dont exactly know what the displace bounds parameter under the render tab does. The higher the value the more…? Im just not sure how to use it. Any other suggestions would be great.


Harvey

I dont exactly know what the displace bounds parameter under the render tab does. The higher the value the more…?

..the more distance the renderer will consider for geometry to displace and the higher the render times. Typically this is the value you will want to increase to remove artefacts. Start at 0.1 and slowly increase until they go away.

Unless of course it's an entirely different problem. Try this first though…

Cheers,

J.C.

Thanks alot for clarifying that JC.

The model that I have this extreme bump layers attached to looks better under a displace bound of five, yet not entirely perfect yet. Sure the render time has soared through the roof, but Its really important to get this effect. Does anyone else know of anything else I can tweak?

Something's wrong here. First off - are you just doing this for a bump, not a displace? You say “bump layers”. You don't need displace bounds if it's a bump.

Secondly, if you're setting your bounds to 5 and it's not solving your problem, it sounds like the scale of your entire scene is out of whack(as in many hundreds of thousands of units across). Rarely I'll set bounds to as high as 2, but that's rarely. Try shrinking the scale of your scene down by an order of magnitude or two, if it's that large. No point in your render times going through the roof.

Alternatively, this may not be your problem - you don't say if this started to fix the problem. You should see marked improvement as this increases.

It's also possible you're approaching whatever you're trying to do in a less-than-efficient manner. Perhaps you can give a synopsis?

Cheers,

J.C.

JC, I must agree that I am approaching this project in a less than efficient manner. The scale of my models is astronomical, because I am trying to create a self contained world within a sphere(sphere dimensions are 191, houdini units in all three axis). I then painted a landscape on canvas, photographed and tiled the painting so that it wraps to the inside of the sphere. This creates my“world” inside this I have models in an array of sizes. Heres a shot inside my scene

The problem geometry is the tree-like model with the bumpy surface. I am using displacement layers(sorry for the confusion) and the displacement amount is set to 0.5. The problem with decreasing the size of the whole scene is that I was hoping to have a continuous flyby shot from down below (like the the pic I have posted) all the way to the top of the problematic model where I have a dwelling and character modelled. I knew the scale issues would be a problem when the shadows for my small models (on top of the tree like object) began to be irregular and not show up properly. The solution for this was increasing the over all model size and the shadows were fine.

I have seen a marked improvement when I increased the displace bounds. I understood that increasing the shading quality might help aswell, is that correct?

So my main problem is that at one end of the spectrum, my scene is too big, and at the other end my scene is too small. Editing between shots, and changing the size of the overall scene accordingly between shots is the only way I can see around this. Thanks a ton for the info.

here's the link to that pic, looks like I cant figure how to post it here.
http://www.geocities.com/fireseal_17/andrew.html [geocities.com]

oh yeah, all my textures are hand painted and then digitally photographed, and I tried my best to map them properly. I am really interested in getting away from the crisp clean lines of digital art, to create something painterly and viscous.

With closer inspection of a test render that just finished, the displace bound set to 5 took all aterfacting out. So I'll slowly reduce that value to find a happy medium between no artefacting and a reasonable render time.