Sectional Plan Rendering

AkaBear

When rending an interior as a sectional plan in for example an axon-metric format, how do you do the lighting for rendering such that the light enters only via doors and windows and not just over the top of the cut wall?

I would probably attempt it in vray.

I saw some nice illustrations recently but am clueless how to achieve it.

Any input most appreciated.

Gaieus

Not every renderer can do it, only those that can use double sided materials (V-ray can). Paint the ceiling with a transparent material fro above and paint it with your normal material from below.

At least that's how I understood ThomThom's explanation (as I do not use V-ray at all). This would work in SU, too, although when using dummy, png's with transparency, you do not even need to add an interior paint as transparent png's cast shadow anyway.

thomthom

Yes - that is correct. That is the method I used here: http://forums.sketchucation.com/viewtopic.php?f=81&t=22423&p=189584#p189584
A simple model illustrating the setup: http://forums.sketchucation.com/viewtopic.php?f=322&t=26866#p231923

Gaieus

Thanks Thom, I could not remember where I read about your method.

thomthom

@gaieus said:

Thanks Thom, I could not remember where I read about your method.

I think I described it more in depth another place - but I could not find that thread now. Think it's in the V-Ray section somewhere...

AkaBear

Thanks, I will try this out. Funny how what appear to be very difficult techical issues are often solved by very simple solutions.

AkaBear

I often ask questions but thought it only fair to post an answer.

So, I tried what was suggested over numerous trials until I got a successful result ready for later use.

Key points I found for a successful cut section render were as follows:

Omni light (not rectangular light) with high intensity setting set as a virtual sun.
Sufficient apetures
Good position of the Omni light to optimize shadow lenght and depth and interation in the space

All sunlight and daylight turned off

But found this to be a bit dull and many dark spaces on the plan so to compliment:

Rectangular light set as a ceiling at a very low setting to give an ambient background/backup illumination.

And the technique works a treat, thanks.

thomthom

Good to hear alternative setups.

AkaBear

If an alternative it was probably because I didn't ready your solution well enough.

But if it is different then cool as there is more than one way to do it!

thomthom

I used Sun/Sky as external light source.
Omni and Rectangle lights as interior Light sources.
Then it was the ceiling face with the side facing the interior a solid materials, and the other side facing the camera 100% transparent.

Maybe you can post some screenshots of your results when you tried to follow my method? That way we might be able to see where I could clarify my descriptions.

AkaBear

Attached was a 2 min model constructed for testing, giving in principal the results wanted.

Would need to be toned for a real project.

thomthom

You forgot to attach?

AkaBear

http://s845.photobucket.com/albums/ab12/halceon2007/?action=view&current=sectionalrendertest01.jpg

Hope this works, didn't have any success with the uploading.