Compute Terrain Smooth Surface And Noise

Started by efflux, January 25, 2012, 05:38:47 pm

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efflux

On a couple of planets I did a while back I noticed lots of noise. At the time I wasn't sure what was causing it. I started tweaking a new planet and found it to be computer terrain smooth surface. The larger the gradient patch size, the worse the noise. Nothing unusual about my planets otherwise. I tried a simple set up and smooth surface still causes noise. See pictures. This is a few metres from the ground which accentuates the problem but mostly if you use any reasonable patch size you'll get noise which gets worse as you add more details to the scene. However, the whole planet still gets noise seen at various distances. Large patch sizes are impossible to use. I'm just wondering what's going on here before I go any further on new work because I want to use compute terrain smooth surface. Anti-aliasing is set to 1 to show the problem better.

Three renders in this picture.

Top:      No Smooth
Middle:  Patch Size of 5
Bottom: Patch Size of 20

Go further and the whole planet becomes a disaster.


Tangled-Universe

Can you post a tgd of this? Just to be sure.

Oshyan

Possibly try increasing Displacement Tolerance in your planet node. A value of 2, for example (instead of the default of 1). Though without looking at your network/TGD I can't say for sure if that would help at all or has anything to do with your problem.

- Oshyan

efflux

Hi Oshyan.

Displacement tolerance doesn't work.

I've attached a simple file here where I replicated the problem from the default TG2.

I'm using near real world type scales now so quite often I have the camera close to the ground. Maybe 2 metres or even nearer. The gradient patch size in this file is quite high at 100. Although sometimes I'll use a setting like that. It is an extremely useful setting to create natural looking terrains. It seems it is not possible to set the camera up at real world levels i.e. 1 or two metres with this feature enabled. A typical set up would be to have the camera very close to the ground so in a big wide shot you see foreground detail that is not even near the camera. The noise is still there.

Two of my last planets had this problem due to being real world scales and setting the camera near the ground. There was noise all over the place. I couldn't understand it at the time. Now I realise it was nothing to do with textures but this smooth surface setting. Also, the camera is generally set up in places where the smooth surface is not actually visually doing anything because these areas are flat anyway.

Matt

I see the same problem here. It only happens when smooth surface is enabled. I also tried to recreate the problem with a Surface Layer that has smoothing effect turned on. They should produce similar results, but they don't: the layer with smoothing enabled renders correctly. I will look into it.

This suggests a possible workaround. Don't use smooth surface but create the smoothing affect with a Surface Layer right after the Compute Terrain, with smoothing effect turned on. I am not 100% certain that it will produce the same look that you're after, but give it a try.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Dune

QuoteThe gradient patch size in this file is quite high at 100. Although sometimes I'll use a setting like that. It is an extremely useful setting to create natural looking terrains.


Can you tell me why you need such a high patch size and smooth terrain? What is the difference in terrain features compared to the normal 20 or so?

efflux

OK thanks Matt.

I'm working on a planet at the moment which uses the smooth surface but the problem is not cropping up as much on this one. The patch size is smaller. There is another planet I'd like to revisit and fix but it kind of relies on the smooth setting for it's character.

Just one more point. I noticed that in some quite heavy problem circumstance where I pushed to get this problem, the black noise was all over the place, even in the sky.

As for patch sizes. Bigger patch size smoothes more. I haven't really experimented to see exactly the differences but small is usually quite adequite. I just set it to what looked OK at the time. In my opinion it is one of the best features for creating some subtlety especially if you use it after strata and outcrops because it tames down the severe horizontal lines.

I thought I'd had enough of procedural landscape designing. Was at the end of it with going back and forwards to Mojo and TG2 but it's over for Mojoworld now as far as I'm concerned. This is tragic because Mojoworld does have some unique features and is very powerful in terms of fractals but render times and UI alone kill it. I feel like I'm finally there with TG2. My quad core makes a big difference of course. I won't be ditching this angle of graphics now. I'll just do it when I feel like it. I won't be tearing my hair out over it.