Matte Object - Shadow Quailty?

[Alan Iglesias]

Hello everyone,

I searched the forums on this issue, but didn't find anything really difinitive...

Since using Vray as my full-time renderer, this will be the first time I am dealing with a camera-matching scene, along with a background plate and a couple of simple matte objects to catch shadows and reflections. I'm using a single Vray spherical light and some environment light.

Everything seems to be working properly, but I am very disappointed with the quality of the shadows on the matte objects. They are completely opaque and quite ragged around the edges, nothing like the shadows I'm used to from the renderer in general.

Is there some way to increase the shadows' quality at all? I know I can do some separate passes and composite, but this project doesn't really have the budget for it, so I'd love to do it "in-camera" if at all possible.

Thanks so much in advance for any light that you may be able to shed on this.

-Alan

[Morbid Angel]

shadow quality depends on the sampling settings inside your render. Increasing the sampling will increase the quality. Another way to increase the quality is to increase the shadow subdivisions in the light itself.

[simmsimaging]

I have this problem a lot too. I've more or less given up on getting a shadow pass from Vray unfortunately - always just too many artifacts and I have to go to extremely high settings on the main render which gets counter productive.

I'd love to find a good solution/workflow for this one too though.

b

[Alan Iglesias]

Thanks very much Dimitry, and Brett, for your responses.

Dimitry, just so I am clear, by "sampling settings inside the render", you're talking about the Image Sampler, correct? And by increasing Shadow Subdivisions, do you mean the Subdivs parameter under the Sampling roll-out in the Vray light?

Brett, I'm hoping that increasing the basic quality of the matte object shadows is something Vlado can work on for future releases. If I cannot get this to work, I may experiment with a basic shadow map with a high sample range to see if I can get the effect I want.

Thanks very much again!

-Alan

[Morbid Angel]

no i ment shadow subdivisions in the actual light. I don't think there is a way to increase sampling for a specific render element.

[Alan Iglesias]

no i ment shadow subdivisions in the actual light...

So if you please, where exactly do I adjust that parameter? I looked around and didn't find anything - have I missed it?

Thanks very much,

-Alan

[Morbid Angel]

select vray light/modify panel/sampling section/subdivis.

[Alan Iglesias]

Thanks very much Dimitry...I'll try that and I appreciate your help very much.

Brett...in the meantime I did find somewhat of a work-around - at least for this job. I tried using a standard max direct light with area shadows. Max's extensive shadow controls allowed me to adjust the sample range and density of the shadow until I got a reasonably good effect. I hope this might help you and anyone else reading this thread who might be working with matte object shadows. Vlado, if we had the same shadow controls with Vray Lights, we could stay with Vray.

Thanks again for all of the help I got here...

-Alan

[simmsimaging]

Thanks Alan - I will try that next time it comes up.

b

[Morbid Angel]

I do not think vlado can do anything about this. There are all the controls for shadow you would need already implemented. When you used max shadow controls, really its just translated into vray so vray already supports that.

[Alan Iglesias]

I see what you are saying Dimitry, and although it can sometimes be a bit confusing to figure out exacty what "Max stuff" (lights, materials, etc.) is cool to use with Vray and what isn't, it's good to know that these parameters are working so well with Vray or "translated", as you put it.

But it sure would be nice to at least have shadow density controls for the matte object, in with the matte object parameters in Vray Properties. That way you can stick with Vray lights in these situations. I'm sure you'd agree that consistency is good while in production.

Thanks again,

-Alan

[Morbid Angel]

Im unsure of what you mean by shadow density?

[trixian]

Maybe density of the matte-shadow, as in setting the alpha contribution spinner to something between -1 and 0 ?
If not, then I don't know what he is on about.

[Alan Iglesias]

Dimitry (and Christian), the 3DS Max Direct Light has a Shadow Density parameter (Direct Light/Shadow Parameters/Object Shadows/Dens.). This controls the opaqueness of the shadow and was very useful in "taming" the ultra-opaque shadows on the Vray matte object.

In fact, I locked off three different lights to three different matte objects (the ground, the side of a pool, and the pool water) and dialed in three different shadow densities for each object. This really helped the image and "sold" the shadows and of course the overall shot.

Thanks again,

-Alan

[vlado]

To use the shadow color/density parameters of standard lights, you need to turn off the "Transparent shadows" option of the VRayShadows shadow generator.

To do the same for matte objects, adjust the shadow "Brightness" parameter in the "Direct light" section of the V-Ray object settings dialog.

A better way to make shadows brighter might be to use the VRayAmbientLight light type.

Best regards,
Vlado