Shadow cast problem in render

[Anonymous]

Windows 10, 3D Max 2017 64bit

Okay so i attached the render out come here, and the problem is the render seems to have places where is shadow is not casing for some reason and there is a light leaking onto the roof witch i'm also not sure as to why, can anyone please help me out as to why this is happening, the only lights i am using are the daylight and mr Sky Portal render type is mental ray, if there is any extra info is needed to know to understand why this is happening please let me know.

Thanks

[Francisco_Penaloza]

The light in the ceiling is the bounced light from your Skyportal. be sure to place some floor under your house-room, place a large geometry to simulate the rest of the planet, this will help to bounce the light better, but overall your settings seems too interpolated that why you are not getting correct shadows and that overbright on the ceiling is exaggerated.

can you post your FG settings?? are you using GI too?

[Anonymous]

I changed the Shadow settings on skyportal and turned off "Outdoor" shadows and it fixed almost all the problems but now the blue wall seems to be too bright, i'm not using any GI but i'll post the new render along with the FG settings

[Francisco_Penaloza · Accepted solution]

The outdoor shadows thing, fix the same problem that I referred with placing a ground plane under your building.

Be sure that the blur/purple wall is not 100% saturated color. Be sure there are no gaps or openings.

Your settings seem a little extreme, but if you have a machine that can handle and time, then it should be fine.

Your interpolation is too high IMO that will create those bright areas in the corner and lose detail in small crevices. Try with a small value in your interpolation. 50 or so should do with respect your other settings.  Interpolation should be used to erase the splotched created for the low quantity or ray samples,  if they are too far apart then it will create a dark area in between then interpolation will help you to erase those and speed rendering a little. but if you interpolate too much, then you will lose small details.

You don't have too glossy materials in your scene, so lower your noisy filtering to default.

You can also unable AO in the shaders itself, that will help to define better your geometry. That is better than applying AO in post anyways.

[Anonymous]

Thank you so much for your help and time too means a lot, i'm still new to lighting types and settings so i'm not sure about what i'm doing there, I enjoy modeling a lot and this is the first time i'm working on a full on room render, your tips helped the quality go up by a lot and cut down on render time too, if you know of any tutorials to help learn mental ray lighting i will really like to know.

Thanks again.

[Francisco_Penaloza]

The problem with Mental Ray is that is a dying render engine, it is not supported by Autodesk anymore nor by NVidia, who used to own it. There still some legacy support for don't hope for much.

Learning Mental Ray today IMO is a waste of time.  You should look into other render engines such Arnold, that comes with 3D Max now, also Corona Render or VRay.  You have the GPU based render engines such as Redshift, Octane, Fry render and many more.

Any of these renders are currently live and kicking and would be a better investment for your future as an artist.

If for some reason you need to stick with Mental Ray, the help docs that comes with old version of 3D Max are pretty good, Tutorials as such I don't remember any, I think I wrote one long time ago in Evermotion website, not sure if still there.

Best luck.