Photonmap vs Lightmap

[Leftover]

Hi,
I've been exloring advantages/disadvantages of photonmap and lightmap modes. The biggest differense between Photonmap and Lightmap is "indirect" shadows precision. (on attached image you can see lack of shadow behind pillows)
I do understand main concept of both modes, so im looking for practical advice rather.
Is there way to overcome this llightmap shortcoming? Or it's unbeatable nature of lightmaping? What do you do in such situations?

[bigstick]

This is something I have also wondered about. Light mapping (for me at least) is always noticeable faster than photon mapping. Consequently I always use light mapping. As for anything else, like you I have no idea.

A little explanation, along with some guidance as to what sort of scenes are best suited to each would be very helpful.

[darickster]

The difference is huge, really got me thinking to change my strategy. Always used camera tracing because it lights up interiors way faster.

If i am not mistaking the number of rays gets devided by lights so not all of them will be used to light the image (for instance light in another room). So if you have direct lights with a clear origin in view as is the case here lighttracing is always prefered. In case where you only use natural light and you have problems getting enough light into the scene without adding extra tricklight cameratracing will add a lot.

Lets say you want a light in the back of the room to have effect on the image it will be easier in lighttracing mode to see its effect as camera rays have trouble getting there.

go correct me if i am wrong..

so in order to have lighttracing working efficient for you, you should be turning off lights that wont be effecting the image. A question that pops into my head now is what calculation method is best to use for animation?

cheers

[silverlw]

Sometimes photonmapping is superior, sometimes lightmapping, it depends on lightsources used and what you try to accomplish.

One weakness of lmaps are the lack of precision and that it's hard to get a well defined irradiancemap but the strenght is that you quickly get a blurry overall lighting and it works with all kinds of lightsources.

One weakness of Photonmapping is that you have to shoot quite alot to get enough photons in hard to reach places but the strenght is they produce a much more improved irradiancemap with well defined shadows.

One way to help photonmaps to get in to hard to reach places is to add skyportals so they dont need to be fired randomly. Since almost every photon hit's it's much faster and close to using Lightmaps.

[weepul]

Would it be possible for Kray to be programmed do a photonmapping pass, then in areas with too low a photon density, do additional lightmap tracing to fill in?

[silverlw]

Well what about a hybrid where direct and strong lights are photonmaped and the rest lmapped?

[Captain Obvious]

Use light mapping, but on the FG tab set the "paths" to 1. This means it actually does path tracing in corners and other areas that are problematic for light mapping. Works well.