Cutoff for light rays

[Siahpoosh]

Hi
first i want to say thank u for your great render engine its very fast and stable for me. i have a exterior scene with more than 30000 lights , i created a sample scene with 30000 lights and a plane as ground , after hit render button i got too much noise also if i zoom on a area for example frame 10 lights render is noisy again and long render time .
if i have an option to cutoff light rays at a distance radius , my render will be much faster. (something like cutoff in vrayLight)

[Ludvik Koutny]

No...  it just does not work this way. Renderers are not the same, so what may work for vray may not work for corona, or may not even be possible in corona. Also, UI should not be cluttered with stuff like this.

It's simple, just do not make scenes with 30 000 lights...

There's 250 light limit... (it's quite dumb the limit is so low... could be at least twice as much till light sampling stops being effective, but nothing we can do about that...) more lights than this limit will slow down the scene dramatically. BUT you can use geometry with CoronaLightMTL instead of lights, and attach geometry lights together to create light groups. Then group them together until total light object amount is under 250. That should work.

But unless you have a specific reason or request, then do not create difficult scenes on purpose. If you have a huge city, with 30 000 lights, then lights in background can be easily swapped for self-illumination materials (NOT CoronaLightMTL!!!) and no one will ever notice.

I do not understand why people tend to just create difficult scenes and throw it at the renderer. That will never get the job done...  with any renderer.

[Ondra]

As I've said many times, I will not implement this feature. I will instead try to improve sampling algorithms.

[zzubnik]

There is no point in wasting development time to implement 30,000 lights. As said above, that is just ridiculous!

[Siahpoosh]

thank u guys for answers . in vray i wrote an script for merging light objects 100 by 100 to vraylightmesh and its helped me so much for speed up render to 20x , but the problem is i need more speed , corona by default is much faster than vray in my situation . i tried to merge lights together like before but its not help. i got much better result when using Coronalight (for every 30000 lights)

[Ludvik Koutny]

Can you post the practical example of a scene where so many lights are required?

[Siahpoosh]

Can you post the practical example of a scene where so many lights are required?

for example something like this :


i have a very large city in night with 4000 cars and each car have 4 lights (2 front and 2 back) and i have long shots , medium shots and closeup shots from my city.

[zzubnik]

I'm not sure this is the type of render that this type of render engine is made for.

[Ludvik Koutny]

Can you post the practical example of a scene where so many lights are required?

for example something like this :


i have a very large city in night with 4000 cars and each car have 4 lights (2 front and 2 back) and i have long shots , medium shots and closeup shots from my city.

Exactly as i said above. Everything in background, that's not center of attention, can easily be solved by self-illumination feature of CoronaMTL. It is not sampled as explicit light, so it does not matter how many of them you have. Yet it will illuminate it's surroundings. Just do not use self-illum as a key light in your scene. As a sun, or main lamp, or something... But if you use it to light up windows in distant buildings, lights on cars, street lamps, etc... it will work.

I can not even imagine it would be efficient to create this scene by manually placing light sources. It would make a lot more sense to create about 10 different buildings, then create self illumination maps for windows, for example one map for entire building, and then scatter those buildings around in the background. I can not really imagine you would have manually placed lights in such a huge scene...  i am not sure 3ds Max viewport could even handle it at workable framerate.

[Ondra]

I wouldnt mind if somebody actually had similar scene and sent it to me for research ;)

[zzubnik]

Unless this was for a giant flythrough, much of that would be matte painted, if we're talking movies.

[maru]

I would approach this with as much fakes and procedural generation as possible. :)

[Siahpoosh]

RE: Rawalanche
i have flythrough camera on the city and also i have animated lights based on distance from a point . something like this :

i cant fake that with mate painting or ...

RE: Keymaster
i can make a sample scene if u want.

RE: zzubnik
yes i have a giant flythrough , as i said in top of this post i cant fake that with matte painting or other solutions.

RE: maru
actually i wrote a lot of tools for doing this procedurally , my scene is fully optimized the only problem is count of lights , and there is no solution for that.

here is an comparison of my main road lights in city between coronalightmtl and coronalights after 20min :

[Polymax]

As I've said many times, I will not implement this feature. I will instead try to improve sampling algorithms.

+1000000

please don't make a vray

cutoff - very bad idea!

[Siahpoosh]

here is another example , Bidir/VCM as render enigine :


result is much better than others , can anyone tell me the limitation of using Bidir/VCM ? i read somewhere its not support all features .