Cycles - What's going on with...

Support Lighting and Rendering
1

Hi guys,

I’ve been using Cycles for a while now and have come across several issues, maybe they’re obvious to fix, but I’m scratching my head here.

  1. First up I have a bathroom scene, it’s been rendering fine with Cycles, but as soon as I added some more detail, eg polygon tiles for the bathroom wall (for realism-bump/disp map texture just won’t cut it) blender renders the BVH ( 4 minutes approx) and then nothing, the render says finished/time count, but the scene didn’t actually render anything out - just a black image.

This isn’t the first time this has happened, I was rendering my Golf Mk4 model a few weeks ago, until I placed it in a simple room with lighting and then it happened there.

Im using Win7 64bit, 2.61, with 7GB memory, Core I3, Nividia GeFroce GTX 350 TI - Rendering with Cuda.

I’m assuming it has something to do with the size of my scene, but it doesn’t appear that big and I never had this issue with BI and the scenes sometimes were much more complicated.

I thought it may be to do with using modifiers, such as arrays, bevels, subsurfs etc. Finalising them doesn’t help.

What’s going on, anyone else have the same issue? and maybe some help pls?

  1. For this lovely bathroom scene I have a closed box room, one window (no glass window-pane) and a lit doorway.

For the window opening I have tried both the Sun lamp and an emitter plane placed outside.

For the doorway an emitter plane (out of shot).

If i bump up the values for emission, why does the the window frame not anti-alias correctly? as soon as you go over 10 or 20, the edges become rough and jaggy.

I get the feeling that the path tracing the cycles uses doesn’t work well for this type of render.

Plus there’s very little contrast as shadows/lighting is extremely soft.

  1. Similar to the above, if you make a lightbulb for a car headlight, how do you get it to emit enough light without needing a value of over a 1000+ and additionally without introducing bad anti-aliasing for the edges? Seems the smaller the object the less light it can omit, this isn’t very realistic.

Am I starting to see the limitation to blender Cycles? After using Luxrender I think I’ve been a bit spoilt.

What type of render is Cycles for? Animation is out (takes too long), interior shots with windows is out - is it just for rendering little models in a studio environment? I’m stumped and confused! I’ve been looking forward so much to Cycles since it was first announced - I was hoping it would solve a lot of problems I had with BI, but it’s just raised loads of others. :frowning:

Anyone got any advise?

2

There is no anti-aliased issues, but it looks like it is. I was fooled by it too some time ago.

You already have perfectly anti-aliased scene, but color clipping to [0.1] range make it look as it is not anti-aliased. In short, imagine 3 nearby pixels. One very bright, like 1000. Second pixel a bit less, 500. And most important, third pixel with value between [0.1], say 0.7.

After output image color clipping, we get 1.0, 1,0, 0.7. And you see huge change between 0.7 and 0.1, and treat it as alias, but it not, because actual colors 1000, 500, 0.7 and resemble very steep but smooth gradient.

I am sure you must to save image as HDR, then use tonemapping and get proper result, maybe there is simple composer node setup but i not familiar with them. Or keep light sources at lower values, to make more pixels in range [0,1]