Inconsistent rendering of same scene.

Kevin F · February 04, 2007, 10:33:33 AM

I am repeatedly getting differences when running two simultaneous sessions of TG2 to render two halves of a file.
The attached jpgs show the full scene and a blow up of the top central area. This is the boundary between the two halves, clearly showing a colour difference. Is this a bug or will there be small differences like this? It's worse or more noticeable in this blue/grey sky area, and doesn't show up in the other "busy" areas of snow and rock.
Any ideas?
Kevin

Will · February 04, 2007, 10:52:25 AM

there was a simular thing like this just with populations not clouds, it would seem to be (at least for me) to be a GI thing with a diffrent calculation of each scene but I'm sure other know more about it than I.

Regards,

Will

old_blaggard · February 04, 2007, 11:22:06 AM

Actually, you're right, Will. The GI is calculated differently for each side. I'm not entirely sure, but I think that if you change either the camera position or the image size, it is calculated slightly differently. This is why some people have experienced flickering while trying to animate.

Arkanias4 · February 04, 2007, 11:40:07 AM

Had the same problem with clouds colours, rendering sucessively 2 crops of the same scene that couldn't match.
By the way, love your thick snow and I would be interested in understanding the way to increase the thickness of snow. I tried already using some file from the forum but didn't suceed really to achieve a real thick snow.
Bernard

Cyber-Angel · February 04, 2007, 09:58:57 PM

Would the situation be helped if Terragen automatically generated mipmapping, which form my understanding is used in 3D game engines to prevent flickering during animations? Maybe some thing for the future.

I was thinking that Mipmapping might help with populations as well when they are extremely dense to help prevent artifacts at the horizon unless there's some technical reason why mippmapping cannot be used with 3D space!

Regrads to you.

Cyber-Angel

BPauba · February 06, 2007, 09:59:47 PM

in tg0.9 I did many panorama renders that I cropped together and I would run into this problem many times. I cannot say I have done any panorama renderings in tg2 I can tell you that the camera wideness subtly effects the lightness of renders. This could be the problem so I would look into that if you could. It was called "zoom" in tg0.9, if you believe this might be it I can further explain my problems and solutions!

Kevin F · February 07, 2007, 03:14:23 AM

Quote from: BPauba on February 06, 2007, 09:59:47 PM
I can tell you that the camera wideness subtly effects the lightness of renders. This could be the problem so I would look into that if you could. It was called "zoom" in tg0.9, if you believe this might be it I can further explain my problems and solutions!

Thanks, but that doesn't apply here. The scene is totally unchanged in each render. The only difference is the cropped area for each rendereing, i.e. each half.
Kevin.

Arkanias4 · February 07, 2007, 04:21:55 AM

My example of rendering with 2 crops: First I rendered the left part you see on the image I show. Then later on I started what I wanted to be sort of the second half of the job and I saw the beginning of the second crop as the strip you see in the middle of this image here. Very different. Finally, I did a full render again later on and the full image looked like the left and right part of the image I show. Which shows that the first left crop was as the full image in terms of colour.
I've no explanation for that.
Bernard
PS Thanks again for your help Kevin.
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jo · February 08, 2007, 04:21:56 AM

Hi,

This problem is that TG2 calculates a different GI solution for each cropped area. I'm not sure if there's usually a problem in parts away from the join of the crops, but AFAIK there is always a difference along the join. This problem will be addressed in the future. If you can live without using GI then you should be able to get cropped parts of an image to match ok.

Regards,

Jo

Kevin F · February 08, 2007, 04:53:26 PM

Thanks Jo,
Didn't really need GI on anyway! I'll try the same file run again overnight.
Regards
Kevin

Tangled-Universe · February 08, 2007, 05:31:54 PM

Quote from: Arkanias4 on February 04, 2007, 11:40:07 AM
Had the same problem with clouds colours, rendering sucessively 2 crops of the same scene that couldn't match.
By the way, love your thick snow and I would be interested in understanding the way to increase the thickness of snow. I tried already using some file from the forum but didn't suceed really to achieve a real thick snow.
Bernard

- If I remember correctly - you can "thicken" the snow by adding a child snow layer. Then go to the parent snow layer and go to the displacement tab. Choose your child layer as displacement function and increase displacement factor. How much is difficult to tell, you should play a little, but I believe it was something like this.
I also read somewhere it had to do with the "intersect underlying" function, but this gives crazy results and I don't really understand what this function is about.

Kind regards,

Martin