Urgen question

[Miguel]

Ok, somewhere in this forum I recall that you could render the irradiance map for an animation every 10 frames, and then use it for the final rendering, is this correct? will the animaten look ok?

Thanks for your help, this is urgent!

Miguel in dire need

[travistlo]

yes this is correct. The way the Irr. map works is it create a 3d map of light samples from the camera to the scene. This means that it only adds samples where the camera can see. If you use incremental add to map as your saving method, it will add the new samples to the Irr. map. You have to be careful that something doesnt get skipped in the irr. processing though. This can happen if your incremental frame rendering is too high.

Lets assume you have an object on the wall of a hallway, and your walking past.

Frame 1- no object in scene, samples are produced, and saved.
Frame 3- Object appears in scence -(no rendering of samples yet)
Frame 9- Object leaves scene - (still no samples for that object)
Frame 10- no object in screne, samples are calculated, and added to the previous map.

When you go to render the animation using the presaved irr map. WHen that object enters into your cameras view, the irr map doesnt have any samples for the object, and will get errors.

Basically, im just saying aware that this is possible, but with 30 frame/sec most of the time it is unlikely.

Hope im making sense. if not, someone will correct me

[Miguel]

Thanks lot travistlo, you saved my a... life. I'm rendering a static scene, its just an architectural fly-thru, so no moving objects entering the scene here.

Thanks again man,
Miguel

[travistlo]

i was talking baout static objects, my point was that you have to make sure the camera will see everthing at some point during the irr map calcs

[Miguel]

Ok, I got it, the camera moves slowly, so I don't think that it would be a problem.

Thanks again

[Miguel]

I have another question, does the irradiance map file size have an impact on the render times?.

Thanks.

[percydaman]

in a way it does, since the higher the resolution of irradiance map (the quality) the higher the file size I believe, and vlado has said the render time will be a bit higher. So the increase in rendertime is only coincident to the file size. but its there.

[Erik de Graaf]

It can actually increase a lot, on complex scenes i sometimes had an irradiance map of more than 400 Mb . Having to load a file this size into the memory takes some considerate time, this especially affects rendertimes if your scene itself is already consuming the most of your memory. I usually make my maps between 100 and 200 Mb.
Somewhere between 15 to 30 frames per irradiance map (720 x 480, medium animation settings), rendered every 15 frames for slow moving cameras, this results in a lot of jobs to submit but will give you better rendertimes and you will finish your project sooner. 1 minute per frame decrease on 5000 frames is a lot of time.

Erik

[Miguel]

Yes I just proved it, a bigger file means longer render times, it makes the calculation of the irr map longer and since it is done for every frame, then it can have a huge impact in animations, just a you pointed Erick.

Now I have another question for you, I'm aware that there are a lot of factors involved, but how can I make my animation rendertimes lower, I mean, when you have finished with light, textures and the such and your escene is ready to render, what is the first thing that you do to lower animation render times?

Thanks for your answers.
Miguel

[Erik de Graaf]

If my scene needs to be tuned i sometimes decrease the reflection and refraction depth, i also make sure that small or complex objects don't have unnecesary reflective materials since you won't see them in the animation.

Make objects low poly that won't come close to the camera.

Sometimes we chop up a scene to render in different cameramoves, you never see the whole scene in one camerashot, just be carefull you don't remove anything that is visible in reflections or through glass.

Erik

[Miguel]

ok Erick, I see, thanks a lot for your comments

Miguel.

[inf3rno]

I have made a movie with add to map 1 each 10 frames. You can see the result here -> http://www.a-3d.fr/video/04.mov


The final result was PAL (25fps).[/url]

[Miguel]

Yes inf3rno, that is a huge time saver, actually I used it in my last fly thru (?), but what I'm tryng to find out, is how to lower render times, no gi calculation. My frames are taking too long, from 15 to 30 minutes and in some cases even more, maybe those are normal times (bet they are not), but when you have a tight deadline and need to use a render farm service, well, becomes very expensive.

Hope that I made myself clear.

Miguel.

[inf3rno]

in my video, rendering was between 1 and 5 mn per frame with Field rendering PAL resolution(cropped top and bottom). IR Map was 10 mn for 3 mn of video (4500 frames / 10 = 450 frames) on dual AMD 2 GHz. My delay was 1 week and i did it.