What The Heck Is Going On?

Started by jackblack, March 16, 2009, 10:02:18 PM

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Ok, all I know is that I slipped up and hit "Ctrl D" or "Shift D" thinking I was duplicating a camera, now my whole scene is super dark with this weird background.

What in the tar nation is going on here?

I attached a tgd file and a pic of what I'm a seeing.

Can any of you guys help me?


It's happening inside your stone shaders, currently digging through them looking for anything odd.


Power fractal shader v3 01, change smallest scale to .1 instead of .0025 of whatever its currently set. Sky and everything seems to render correct again.

A good tip on how to debug scenes like this is easy to do in a few steps:
First just make sure things are flowing correctly, clear out nodes not being used, clean up node view and just see the flow of things.

Now, try to determine whats going wrong. And compare it to the defaults of a blank scene, or the defaults when a node is made. 

Going through your scene:
Sky/lighting is messed up... Ok, lets check atmosphere/clouds/lighting.  After glancing through them, they all seemed reasonable values, barely anything changed from default, so it most likely wasn't the problem.

Thinking, terrain also can cause odd sky/lighting problems where displacement screws things up.  So I first when and disabled all shaders and tested, it rendered fine.  So I knew it was in your shaders.

Then I went through enabling them one by one to see what happened.  One caused major problems, one didn't seem to cause too much problem, and another caused some weird spikes if i recall correctly.  They all had one thing in common (glancing at the node view), that was the power fractal surface shader.  Since they seemed to all cause a little something, I decided to start there.  Double checking later the rest of the shaders used in there seemed reasonable too, so yes power fractal. 

I told it to disable displacement in the power fractal shader, it rendered correct again.  So I confirmed it was in this shader.  Then I checked the values in it to a brand new default settings fractal shader, and the only thing that was quite a bit different (besides things you can ignore like seed), was that you had the smallest scale set a lot smaller then the default, so I set it to default, and wallah she worked again.


Whew, thanks so much, I couldn't figure out what the heck was going on.

That did the trick :D

Thanks again.


Hey thanks for the debug workflow, I'll keep that in mind next time something crazy happens.



just another tip, your scene will render very slow due to the alpine fractal you are using.  One tip to speed up alpine fractal renders where you only need a view of a few peaks, is to use the heightfield generate, flip to use shader, and tell it to use a alpine fractal that way.  This way it will only generate and render those few peaks inside that heightfield generate instead of a whole planet.  Speeds up things ;).   For a few alpine fractals in the background I do the same thing with another heightfield generate, thats bigger in meters size and what not, then put it off in the distance.


Hey, thanks for that tip too, what do you think about creating multiple Height Field Generators and using them all over the planet for continents? I think that may work a little better than the terracell technique for land mass on a planet.


Well now that Heightfield Generator Alpine technique is screwing up my terrain, is there something I'm not doing? I'm trying to match settings best I can.


well they wont be exactly the same or whatever, what kind of idea of a scene are you doing?  Depending on what your doing my method might not be the best choice.

i generally try to avoid using alpine fractals when possible just because its a little on the slow side.


Well, it's sort of a lake, like the ones here in Missouri, I'm not too serious about it, I'm just practicing making good terrains.


heres a quick example of what I do in general.  You take a hit on the generation of the heightfield, but afterwards it speeds up.  Got a camera position that's like your current scene.


In case you guys didn't know (and maybe you already do), anything in the 3-digit range for a displacement can freak everything out.  The lowest I go right now for terrain displacements is .01
So this is Disney World.  Can we live here?


Have you tried replacing the planet for a new one?