Terrain and shadows changing during animation

Started by seanQuixote, March 30, 2010, 06:05:43 pm

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seanQuixote

I'm wondering if anyone has come across this issue and found a way to defeat it:

New to terragen so I made a simple mountain landscape, added a slight off white shader for snow, put in some key frames to do a fly through and rendered it out.  First try and I got some shadows flickering.  I managed to fix that by switching to from GI to AO.  What I haven't been able to overcome are these slight changes in surface detail from frame to frame. A small shadow will disappear between two frames or a small speck of snow on a small ledge will disappear for a few frames then come back a few frames later.  The over all effect is these intermittent spots in various places throughout the scene that turn on and off as the animation progresses which is pretty distracting.

I've done over 32 test renders with various combinations of settings but I can't seem to get it right.

If anyone else has come across this I'd really, really... really appreciate some insight on how to fix it.

I'm attaching the .tgd file... in case some generous soul wants to take a look.


Tangled-Universe

The detail blending is set to 0.
For still images this is just fine, but for animations it is key to increase it up to 1 max.
Decrease the blur radius of your GI and start testing again. Perhaps you don't need it anymore @ 100, so the GI will look better, which made me notice that you've set GI relative detail to 3 and sampling to 2. That's pretty high if you'd ask me.
If you need detailed GI then I'd suggest to render with GI relative detail at 2 and sampling at 4.
This gives pretty much the exact same result, but is much faster than GI 3/2.

Martin

seanQuixote


Oshyan

Agreed, Detail Blending should be at 1 for animations. You may also need to use Ray Detail Region Padding in the Render Settings Advanced tab, if you seem to be getting intermittent shadows from terrain that is out of frame. If so try Detail In Camera with a value of 1.

- Oshyan

MKE

Hello Everyone,

this is my first post here, so I hope I don't talk too much nonsense...

My big boss bought two very nice cinema beamers for 3D projection but we had nothing really nice to show in 3D up to now so this is my job now. I render an animation of a circular flight above a digital elevation model created by a colleague and I think the single images already look quite nice. Just when I started with the animation, I ran into the flickering shadows problem as several people before me (Sunlight a 10° elevation).

First of all: Thanks to all of you in the forum. With your help I managed to reduce errors step by step. On the other hand that means that I was quite astonished and not very happy about the fact that there doesn't exist a manual where you can get all the information from. The node reference is quite a joke at the moment but I hope that it grows step by step. The guys from planetside answer very competent to a lot of questions in the forum. If you would write down these answers to one document and not to a thousend threads you would have a perfect documentation of the software.

The reason why I write:

The shadow problem got much better with "Detail in camera" and a "Ray detail region padding" of 1 (0.1 had no effect, 0.5 was a bit better), but still I had problems that the shadows got smaller when I came nearer. So after trying a lot of other sliders and buttons I tried to enter a number which is outside the "reasonable" values of 0 to 1. With a value of 2 I already was quite happy and with 3 all the shadows stay where they should be. At least I hope, because I restart the complete animation again this evening. My fear about an extremely increase in processing time by inserting big numbers was unnecessary. The needed time is always more or less the same. The trial with a value of 10 was faster than with 3!

So my question: Is there any reason which should keep me from using a very large ray detail region padding (3,5,10,...?) all the time?

Kind regards,
Martin


Quote from: Oshyan on April 01, 2010, 02:14:45 am
Agreed, Detail Blending should be at 1 for animations. You may also need to use Ray Detail Region Padding in the Render Settings Advanced tab, if you seem to be getting intermittent shadows from terrain that is out of frame. If so try Detail In Camera with a value of 1.

- Oshyan

Oshyan

I would be surprised if a value of 3 or more was not impacting render time significantly. That being said I *think* there may be some limitations which effectively mean anything above a certain value (perhaps 5, not sure) isn't going to make much difference anyway. There have been some recent fixes in internal versions which will be available in a future update to partly address this. But for now you're free to use whatever values you want, as long as you don't see an undesirable render time impact.

As for documentation, yes it's something we're working on, but certainly not quite so simple as collating all our forum answers unfortunately.

- Oshyan

MKE

Quote from: Oshyan on March 05, 2011, 03:41:14 am
I would be surprised if a value of 3 or more was not impacting render time significantly.


Hi Oshyan,

Thanks for your answer. The new rendering of the animation is running now since about one week with a value of 10 for ray detail region padding (without impact to render time) and with detail=2 (necessary but with factor 3 in rendering time)  and "most" shadows stay where they should be now. Unfortunately "most" means "not all"... I don't know were I should screw to get this fixed. Setting the sun to a higher position in the sky could solve the problem but that would be an ugly solution. The light is very nice as it is now and I like the long shadows as long as they keep still...

I attached some images and my tgd-file. If you have an idea how I could solve the problem I'd be really happy.

Kind regards,
Martin



Oshyan

I'm afraid I won't be able to reproduce the problem without your terrain file. If possible can you email it to support AT planetside.co.uk?

Thanks,

Oshyan

Matt

There is a problem with shadows cast from behind the camera plane. No amount of ray detail region padding can solve this completely, I'm sorry to say. I am considering some possible ways to fix this.

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

goldfarb

I've downloaded this file and rendered it with the suggestions given in this thread and still get some flickering...

would it be possible for planetside to edit the settings as best they can to reduce this and then provide it as a guide for these kinds of renders - I realize that different scenes will require different settings but many of us would find an example that works as well as possible very handy to use as reference.
--
Michael Goldfarb | Senior Technical Director | SideFX | Toronto | Canada

Oshyan

Quite honestly animations demand a lot more tweaking and in many cases specific settings than stills. In this case I actually finding that "Raytrace Everything" is giving the best results (yes, even with a scene composed entirely of terrain), however this is not something we would normally recommend! So the recommendations would really not be good to extrapolate to other scenes.

If my Raytrace Everything experiments work out I'll post the TGD. I did change some other settings, and interestingly it also reduced render time to less than half of what it was.

- Oshyan

Oshyan

Update: Raytrace Everything also did not resolve the problem. For now this seems to be something that can't be fully addressed but we're working on fixes for a future update.

- Oshyan

MKE

Quote from: Oshyan on March 15, 2011, 12:17:03 am
Update: Raytrace Everything also did not resolve the problem. For now this seems to be something that can't be fully addressed but we're working on fixes for a future update.


Hi Oshyan,

thanks for the troubleshooting. Too bad that there is no fast solution. So I hope that it can be solved for an update. I will not render the whole animation again with a higher sun. The computer is running now for two full weeks and I don't want to throw that all away. I'll finish this animation as it is and hope for the update to render the problematic images again. For the next animations I will use a higher sun and hope for the best.

Kind regards and many thanks for the fast support,
Martin

Oshyan

Here's the TGD for the Raytrace Everything version. Not bad results really, and much faster render time.

By the way you might want to consider turning on the Fractal Detail. I understand accuracy may be an issue in this animation, but I suspect the *lack* of fractal detail is actually contributing to the shadow issues and possibly even the terrain instability with shadows from behind the camera. Something to look at...

- Oshyan

MKE

Hi Oshyan,

thanks for the modified tgd-file. As far as I see you changed:
detail = 0.5 instead 2
ray trace atmosphere = 1 instead 0
GI relative detail = 2 instead 1
GI sample quality = 3 instead 2
GI blus radius = 20 instead 50
detail_jittering = 0 instead 1
ray trace everything = 1 instead 0
minimum threads = 8 instead 1
maximum threads = 8 instead 16
size of subdiv cache in MB= 800 instead 400
ray detail region padding = 1 instead 10

Is there anything I missed? What about the number of threads: Isn't that a problem if I only have two processors?

Unfortunately the quality with detail=0.5 is not really what I want to have. See attached an image example. I also tried with detail=1 and it's better (but not as good as the previous images) but then there's not much time saved any more. Hmmm, I'll do some more tests and then decide how to proceed.

Fractal detail will still be switched off. I want to show the real details of the new DEM and not create more "details" for nicer images. So I can just hope that I don't run into problems because of this. But for the work I do, artificial "details" is a no-go.

Thanks for your help, kind regards,
Martin


Quote from: Oshyan on March 15, 2011, 10:14:40 pm
By the way you might want to consider turning on the Fractal Detail. I understand accuracy may be an issue in this animation, but I suspect the *lack* of fractal detail is actually contributing to the shadow issues and possibly even the terrain instability with shadows from behind the camera. Something to look at...

- Oshyan