Contact shadows, where are they?

[Tim Saunders]

Every time I do an interior that is really bright, with light colors I run into this problem, I can't see any shadows of my chair legs. Lately I am doing a lot of similar spaces, so I would like to find a solution.

 

The scene is set up with a vray plane at the window, a vray sphere in the middle of the room, and about 4 spot lights as cans around the room. I am using IM primary, LC secondary.

 

Increasing the IM rates helps with some of the shadow definition, but I never seem to get any shadows from the chair legs. The spot lights aren't even using area shadows, I thought that would harden up the shadows, but I'm not getting any help with that either. I have even tried adding additional spot lights petitioned lower, pointing right at the legs of the chairs, but all I get is brightness in that area, no shadows.

 

Sorry for the crop, it's a religious project and the client has asked for any images to be kept private.

[Ray]

If you turn off the vray sphere in the middle of the room, does that help? Or is the room too dark then?

[jophus14]

If all of your lights are casting shadows and producing light from all angles that it will be tough to see the shadow from one direction since light is coming from multiple directions. I would just use the downlights/spotlight as your shadow casting light since that would symbolize "true" lighting within a real environment. There wouldn't be lights at every window and a ball of light in the middle of the room in real life. Hopefully that'll solve your issue.

[Ricardo Eloy]

Any chance of at least a screenshot? I mean, maybe the way your lights are placed are causing the shadows to be so weak that you can't see them.

One thing I guess could help is to set your shadow subdivs to something higher than 8.

[Ray]

. . . There wouldn't be lights at every window and a ball of light in the middle of the room in real life. Hopefully that'll solve your issue.

 

I would just try turning off the sphere and leaving the window lights on (as well as the down lights.)

[Tim Saunders]

I may try increasing subdivs, but there is a huge shandelier in the middle of the room, hence the sphere light, so I think I'm pretty close to the way it would be lit.

[Stephen Thomas]

Seems there's a few things it could be. An irradiance map + light cache solution never gives you the same contact shadows as a QMC/DMC GI solution does. You could try and switch to DMC and do a region render of that area just as a test to see if if that makes any difference. Otherwise it could be that your room is just very evenly lit.

 

You could try reducing the diameter of your vray sphere light which will sharpen your shadows (if you have a decay on the light you will need to compensate by increasing the multiplier).

 

Alternatively you could render an AO/dirt pass and overlay that in photoshop.

 

Also remember that if it is really bright outside then the artificial lights wouldn't necessarily be on. So either render with just lots of natural light, or with dim natural light and artificial light and see how that affects things.

[Tim Saunders]

Thanks guys. For the sake of time, I may stick with LC for secondary, and just do a dirt pass. I'll probably even use Brian's caution by only using the dirt pass on the floor. I'm pretty happy with the deffinition in the rest of the scene.

[Derek Forreal]

hi Timothy,

 

i've had similar problems before (table not casting shadows). in that case i managed to solve it by using detail enhancement. it took a few goes but i finally found the 'world' setting @ about 300 - 400mm did the trick. any less and you can see the where DE ends and IM begins. any more and it starts taking too long.

 

but you should satisfy yourself that your lighting is good first

 

OR try raising the quality of the IM final pass

 

hth

 

re AO pass, i think vray is such a quality renderer that AO is not required

[Tim Saunders]

Thanks for the suggeston. I may try DE. I have used it a little in the past, but dind;t want to fuss around with it. Trying out your suggested settings may save me the time. Thanks again. I have 3 rooms that will be finished tomorrow.