irradiance map
laverdet_943f1f7da1
Posts: 252
Hello!!! I have an animation with fur, where the global illumination is very long... there is not really movement of the character, so I think that saving irradiance map would be Wise... I didn't try before: is it just necessary to check "one for all frames", or is it necessary to check "use saved map"n and to calculate first an irradiance map... in other words, what is the function of the saved irr map, versus "one for all frames"... thank you for helping!!!
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in fact, I just try to get, on a "current frame" render, an irradiance map saved... after, i've checked "use saved map", for the animation, but it seems to ignore tghat, and calculate each frame with global ill.... what I'm missing???
Hi celmar.
>To Save an irradiance map.
-Check 'Save irradiance map:' and name a file to save.
-Now render the first frame only and it will save the scenes irradiance map to that file.
>To Load an irradiance map.
-Make sure to uncheck 'Save irradiance Map:' and then check 'Use saved Map:' and locate the map file you saved.
When you render an animation using a saved irradiance map, it should not calculate that type of lighting again for the duration of the animation. The feature, 'One for all frames(static scenes)' is similar to using a saved map in that it won't calculate that lighting after the first frame, but it does not save the map to a file.
Few notes. As far as I know, the irradiance map feature only saves a diffuse part of indirect lighting(the Multi-Pass Global Illumination pass). It won't pick up light bounces from mirror like shaders or specular type light reflections. Caustics is needed for those type of light interactions. Hope this helps.
No matter what you do, hair is going to take forever to render using GI. If you can simulate GI it may be faster.
That being said, you can speed it up somewhat. Something that could help with the hair, is if you use a light with raytraced soft shadows, exclude the hair from it and set up a duplicate light that lights only the hair and has no soft shadows.
What can help with the irradiance map is to do a low-res render of your scene with the Save Irradiance Map option enabled, then render the full resolution scene with the Use Saved Irradiance Map option. The resolution for the map shouldn't matter, and the lower res image will render faster.
I just tested anything to do with irradiance maps for the first time, just now. Never messed with it before.
Instead of saving a map, I just checked the "One for all frames (static scene)" in an animation where the camera doesn't change much, aside from following the figure along the path. here's a gif of the result
Before I changed irradiance map to One, it was taking forever to calculate. But afterwards, I almost couldn't see the calculation box - it was so fast. But this is a very very simple scene with only one shader...
According the the manual, the irradiance map is for the whole scene (maybe it's a spherical map?) What the static scene option means is that nothing is moving so the shadows don't change. You can fly your camera around as much as you would like and from any angle and it should be good. If you stick a horse galloping through the scene, then the shadows will be messed up as they change, but the map doesn't.
Are the shadows messed up in my gif? They seem to be working fine to me....
EDIT: Genesis is moving along at quite a clip in this animation. ~40'!
I was looking at it in the other thread. They look fine for me. I was just going by what the manual said as far as the static scene option. It was my understanding that the IR map is used to distribute the photons in a GI scene. The manual said you could get interesting effects if you had a moving object in a scene that used a static map. Maybe it was updated? I know there were bug reports and feature requests going back quite sometime for DAZ to fix GI animation due to flickering between frames.
I'll have to do a simple test and see what I get in C7.2 Pro.
Since it says right there: Static Scenes, I don't know what there would be to complain about of it didn't work right for animations, personally. I think it's pretty amazing at how good the system works. That's just a single distant light! :)
Reading Birn's book about what's going on for all of that, I think that Carrara is magic at how fast it can do all of this.
The big part to remember is this:
Today's software and computers have come to a point where it's really easy to get spoiled. Today we can just keep adding things to our scenes without a worry or care, whereas just a few years ago, we might have to reboot and try again.
If we want to get fast or even just faster-than-current speeds for our renders, we really have to take a good look at our scenes. 32,000 hairs didn't quite look right. Let's try 537,000... yeah... that's better. Don't stop there. If you really want to optimize your render speed, start working backwards, decreasing that count now, and find out where it becomes the difference between acceptable and not. If you really want it to look super-cool, then go even higher, but then understand that there is going to be a price to pay. There's already a price using hair, but it's well worth the beauty of the effect, in my opinion. I think Carrara hair is simply outstanding looking!
evilproducer and I have both grown accustomed to linking lights. Linking means that the light only affect certain things in the scene. So adding a distant light to come up through the ground, we now have an issue. The ground, itself, is going to block that light, due to shadows. Disable shadows and our characters and creatures will have illumination going on inside the mouth and ears, etc., So instead, we exclude the ground from the affect of the light.
Well you can go even further. You can set up a light that is linked specifically to one object in the scene. So if the above example works really good for the main scene, but not on the main character, exclude the character as well, and make a special one (or more) that only affect the character.
EnvironKits lighting systems provide a great example of a common, yet well-planned overall artificial lighting system. The artificial ambient lights are very subtle and cast no shadows. It's their subtlety that allows that to work well. Woodlands also uses a slight sky-controlled ambient setting in the scene effects, while Badlands does not. There is an additional set of lights for 'focal features' to make them stand out better amongst the surrounding environment. All of these lights are linked to that group - so they actually affect nothing by default. But it allows me to add a setup for added 'Pop' settings for lights that are linked to objects. So now to actually complete that link, all I need to do is to drag something into that group.
So if you have any of the EnvironKits, open up the base scene, or whichever, and check out how I've faked the global illumination. You should also know that I've replicated the fake GI dome lights to make a much higher number than I usually use in my animations. This is because, for the Kits, I wanted beautifully soft shadows as the default, without using the 'soft shadows' option. The magic number I've used is 88. There is a range in there that makes soft shadows. Decrease the number of lights, and you risk getting too sharp of shadows, and getting shadows artifacts where they intersect, if you don't use soft shadows. Well soft shadows will slow down your renders. But in many of my animations, since I really want a lot of speed, I'll go with something like 12 - 14 lights in the dome instead of 88. When I do that, however, I have to increase the brightness to 5 or 6, and shuffle the replicator until most of them are on the side of the dome that I'm looking from - through the filming camera. Much faster renders... more time to set up.
Hey Dart, I'm doing a walk cycle test with GI and a saved irradiance map. The shadows from the figure look fine, but I do notice some of the reflected light has artifacts that don't look like your typical ashing type artifact.
My suspicion is that the GIF you posted is small and limited in the number of colors. I'm rendering a larger size than your GIF with the full color space as opposed to a GIF which is limited to 256 web safe colors. I'm also rendering to an image sequence, so I can post some samples when it is done.
True. It was a tiny render.
Hi Dartanbeck.
When you use a saved irradiance map, you are using a globally baked GI lighting calculation for the entire scene(similar to what EP said). Anything you change or animate after will be offset from that IR maps lighting. This is why only the camera can move without lighting issues.
The PDF manual suggests rendering without textures and save an IR map then adding textures in after which can be used for some different effects. I use this method for controlling GI light saturation(color bleed).
For instance. Rendering indirect light in a white walled room with deep red carpet usually turns the room all pink. If I render with a much lighter color of red carpet first and save the IR map, I can then add a deep red carpet shader on top of that map later and render without the over saturation.
Cool.
Thanks for the explanation. I wonder why it takes so much time off of the initial calculation when only making one map. Perhaps it looks ahead?
For an animation that uses a static map, it only calculates once. For a saved map, the calculation is already done. I was getting a per-frame render time of just less than a minute on my ancient system for my full GI (Skylight and IL) at 640x480 with fast AA set to 1 pixel object and one pixel shadow accuracy. When I added my other machines to the network and copied the saved IR map to the temp files I was rendering at 20 seconds per frame with full GI.
If I were to have a GI feature request, it would be to be able to bake an IR map as an image sequence or something for animations.
Here you can see the artifacts created by the animated movement of the figure with a saved IR map. This is the non-networked render just to make sure that the different machines weren't rendering different gamma levels or variations in the GI calculations for whatever reason.
Here's a link to the youtube video:
https://www.youtube.com/watch?v=cLHnOrEyz3Y