lighting problems Tweet

[alfabruce]

Hi Everyone,
just need some guidance on a scene im building where the lights are driving me crazy.

I have three lights, one large one above, one medium out to the side and a small one inthe persons lap which is meant to be like a torch or lantern.

The scene is unfinished but i have attached a few images to help describe my frustration.

When i turn on just the lantern, it looks like I predict it shold look, but when i turn on the other lights, they seem to override it and the person receives less light to the face. This wouldnt happen in real life, sure they would be in shadow from the main larger light above but the light in the persons lap would light their face very well.

When i used 3D max, it had a light falloff and hot spot etc where the light ould not reach out any further than what was set. Does Octane have something like this and have i got the settings mixed up.

Looking at the boy in the boar closeup, why is the entire boat so well lit, even behnid him when just using the lantern?

I have mucked around with the surfaces and materials butt his should not have this much effect. I would have thought if the boat timber was that bright yellow, his face and jumper should be very bright too.

Is this a GI clamp issue?

Cheers

Tim

[face_off]

Tim - I don't have any answers for you - however if you assign a different Material->Emission->Light Pass Id to each light, and then turn on all the lighting passes you should be able to identify the light contribution of each light and solve your problem. Also keep in mine the Double Sided and Surface Brightness pins which can influence the light emitted from each surface.

Paul

[alfabruce]

Hi Paul,

thanks for your reply.

Those images are the individual light contributions but I cant work out why the bright yellow lamp in the boat next to the boy is reduced so much when the other lights are turned on.

Where do I find the surface brightness pin?

I did find that moving the yellow light in the boat back away from the boy made a bit of a difference. Can a light be too close to have an effect and what controls this?

Cheers

Tim

[face_off]

Those images are the individual light contributions but I cant work out why the bright yellow lamp in the boat next to the boy is reduced so much when the other lights are turned on.

I think you are turning the lights on/off - but instead you need to using the lighting render passes. Can you confirm those images above are from the render passes please?

Where do I find the surface brightness pin?

It's on the Emission node attached to the light material.

Paul

[alfabruce]

Hi Paul,

Thats interesting, Yes I do turn the lights on and off via the layer controls.
I also turn the lights down in power.
I havnt used the lighting render passes as Ive never understood the benefit or reasons for doing so or seen a tutorial showing it.

Does using the render pass work in a similar fashion?

Cheers

Tim

[face_off]

Hi Tim - have a read of https://docs.otoy.com/StandaloneH_DEV/S ... Passes.htm which should also be applicable to the Rhino plugin.

Paul

[alfabruce]

Hi Paul thanks ive been through that and successfully created some lighting passes. I am having problems with the shadows and black background but ill do some more experimenting before I pester you with questions.

My only concern is that being able to see the effect of several different lights in the actual render window is crucial as we all know how bit a part of the appeal of art and images the overall lighting angles, power, shading, colours etc are....they can make or brak an image and hours can be spent trying to get the tone, values and mood just right.

having to do the adjustment later in photoshop with the render layer passes so of defeats the point.

Im still struggling withe the fact that some lights just seem to get over ruled by the others and dont seem to play by the rules of physics and I need to be able to tune the image in the window, not just later in photoshop, thats the whole reason I bought Octane inthe first place.

Any thoughts on things I can try or settings I might have stuffed up somewhere along the line?

Cheers

Tim

[face_off]

Sorry for the delay responding to this. I am unsure of what specific problem you are having. You can assign each emitter to a different Light Pass Id, and then enable each of those Light Passes to see the light contribution to the scene from each of the lights.

Paul