Exterior Shadow Study issue_HELP NEEDED!

[Garrett Gray]

Hoping someone can assist me. I'm doing an exterior shadow study on a city block. I am rendering using VRay 1.5 sp2 and MAX 2009. In the two images attached you will see a building by itself with a shadow casting. When I bring in the massing of the other building the shadow crawls up the building (as it should), but I still see it on the other side on the ground, as if the second building wasn't even there (which shouldn't happen).

 

Any suggestions on how to correct in MAX. Trying to avoid compositing.

Thanks for any help!

Edited September 8, 2009 by Garrett Gray

[Tommy L]

Well it looks like you've told the surrounding buildings not to cast shadows, as none of them are casting shadows.... so the like is going right through them. As the subject building is occluding the sun, the shadow is cast on the ground also.

Quickest fix would be to render two images. One with the building turned off. Then the shadow will not be there, so you can easily combine the two in post.

[Garrett Gray]

Thanks for your comment. Compositing...Yeah that would work, but over 60 images is a bit time consuming! Really looking to solve the issue inside MAX.

[Tommy L]

Then you will have to use the buildings as a shadow/matte. You can do this as a material or as a property.

 

Your image looks a bit weird because some of your surrounding building cast shadows, some dont. Is this intentional?

Edited September 8, 2009 by Tommy L

[Garrett Gray]

I'm not sure how to do that. Can you elaborate please? The shadows on some and not the others is intentional. I have them broken up into different selections to turn on and off at certain camera angles.

[Tommy L]

read the help for matte materials on either the Chaosgroup website or in the Max help files. Im not going to write you a tutorial here, Shadow Matte is the way to go.

[rgb]

Hoping someone can assist me. I'm doing an exterior shadow study on a city block. I am rendering using VRay 1.5 sp2 and MAX 2009. In the two images attached you will see a building by itself with a shadow casting. When I bring in the massing of the other building the shadow crawls up the building (as it should), but I still see it on the other side on the ground, as if the second building wasn't even there (which shouldn't happen).

 

Any suggestions on how to correct in MAX. Trying to avoid compositing.

Thanks for any help!

 

Hi there,

as Tommy L mentioned looks like some of your buildings are not casting shadows or maybe the polygons are facing inwards so make sure that your geometry is either double-sided or facing outwards, second thing i would check is the scale of the scene make sure it makes scene because that can effect the overall quality of your render specially if you are using a sun.

 

and if you have imported your geometry from another application make sure the smoothing groups of the polygons are either 45 or 0 if you don't have any round surfaces.

now not all of the above is directly answering your question but it might help.

Good Luck.

[Garrett Gray]

Thanks to you both! I will look at both suggestions and let you know what I find out.

 

Regards