X3 Ray Trace

[Allen Brown]

Susan,

Can you give me an idea on what number range of photons to experiment with?

For the three different photon boxes; caustic, indirect, & lookup, I don't know if I should start with 5, 50, or 500.

Without some sort of basic idea of what number range is "standard" or in the software designer's "Expected" range, I am really shooting in the dark here.

Thanks,

[Keith Jeffery]

Can you give me an idea on what number range of photons to experiment with?

For the three different photon boxes; caustic, indirect, & lookup, I don't know if I should start with 5, 50, or 500.

The wizard should give you a pretty good idea.

For caustics, I'd generally do something between 10,000 and 50,000.

For indirect I sometimes go up to 2,000,000. The limitation here is usually memory -- the photons can take up quite a bit.

For lookup, I'd generally stick to 50-100.

[Susan Jeffery]

Susan,

Can you give me an idea on what number range of photons to experiment with?

For the three different photon boxes; caustic, indirect, & lookup, I don't know if I should start with 5, 50, or 500.

Without some sort of basic idea of what number range is "standard" or in the software designer's "Expected" range, I am really shooting in the dark here.

Thanks,

Usually the defaults that the ray trace wizard sets will work fine. For sunlight through the windows, I would start with 25 caustic photons.

Indirect photons: calculate how light bounces in the room. In real life, light doesn’t just hit a surface and stop, it bounces off of that surface. So, if we increase the indirect photos we’re getting a more accurate calculation of how light would bounce in the scene. I usually stick with the default (8 for standard), but if I want a little extra "oommff" I will go between 10-15. This will add time to your ray trace. Essentially, you are telling the ray tracer to be more accurate in its calculation and that takes time.

Photon Lookup: we’re determining how many photons the ray tracer will look for. Between 50 and 100 will work for most ray traces. If you use too few, the resulting ray trace can look splotchy. Too many can make it blurry. The Ray Trace wizard does a good job of determining this for you. For most cases, you won’t have to change this number at all.

Maximum look up distance determines how FAR the ray tracer looks for photos. Again, if the number is too small the resulting ray trace can look splotchy. The ray trace wizard setting is probably best here.

For any ray trace, you’ll want to make sure Final Gathering is on. The more samples you set, the more realistic the scene will be. If you lower the number too much, the ray trace can get a “noisy” effect. With no Final Gathering, you may see a “disco ball” effect. Most times the ray trace wizard setting will work great, but if you would like even higher quality – this is a good number to increase.

Hope that helps, let me know what other questions you have.

On Edit, Keith's answer is much more simple that mine! I probably gave more than you were looking for.