help with reflective white floor which recieves shadows

[andrewjohn81]

To describe my scene, I have a few appliances, basically big white boxes, all sitting on a floor. Except the microwave which is just floating.
The floor needs to be white, have some shadows, and reflect the objects on the floor as well.
Also, we are going to do like 40 renderings and we'll need to do them in a short amount of time so I'm trying to figure this out without compositing. The last run we did we just rendered the reflections separate and comped them over. It took forever as these are also huge renders.

It seems that I can always seem to do one thing, but then not the next.

The obvious solution to me seems to be a white background with a matte shadow vray plane as the floor. This creates a nice white background and my shadows are looking fine.

The problem is created when I make it reflect my objects. The objects are reflected strangely, as if they were being reflected on a piece of glass with white behind it. Ha, of course...that's exactly what's happening.

OK, so unless you know how to make a matte object reflect as if it were actually a solid color instead of having the reflections be more like an additive composite then let me know, otherwise I'm moving on to try something else.

So then I wanted to try it with a white floor. Making the white floor reflective gives problems because then you see a horizon line. Then I tried overriding the hdri reflection and reflecting just white. Better, but I have no shadows.

So then I thought, let me try using one plane on top of another. I have a clear plane that gets nice reflections and nothing else. i removed it from GI, it's not being reflected/refracted, nothing. Then I have my original matte plane underneath that, within a few millimeters as that won't be noticed, to catch the shadows.
Rendering that alone makes the shadows looks fine, and rendering the reflections looks fine alone as well, but when I put them together the shadows disappear and the entire floor turns a light grey.

I think I've exhausted all of my ideas to achieve this. I'm sure others have done this, although I haven't seen many examples. Why can't I get shadows on a white background while reflecting my objects, and nothing else, on the ground? This just seems like such a simple thing and I can't seem to find a solution.

Any ideas? I'm just completely stuck.
Please note, my objects are appliances, so basically giant white boxes (yay boring). We're doing a stainless version as well though.

[dlparisi]

Can you post an image - I can't understand exactly what you're problem is and what you're trying to acheive?

[andrewjohn81]

imagine that image, but without the gradient. Unfortunately the company I work for blocks just about every image sharing site. And when they don't once I use it, they seem to find it and block that too.

That's as close as I can find for now.

Basically all I want is a good reflection on the floor and some shadows at the same time while still achieving a white background.[/url]

[^Lele^]

It's a matter, i believe, of law of reciprocity.
Your reflections being too high take away the diffuse coefficient which should receive the shadows.
Try comping...

[dlparisi]

It's a matter, i believe, of law of reciprocity.
Your reflections being too high take away the diffuse coefficient which should receive the shadows.
Try comping...

Yeah, what he said... Basically you're trying to do something that is very unrealistic. I think you're stuck rendering out a couple of passes and comping.

[andrewjohn81]

yeah, I think that's what we'll do. Since all the products are approximately the same I should be able to keep the reflections, then just paint one set of shadows and use that for each one. I think that might be the best workflow.
Plus, I should be able to create an action for that simple enough as long as I keep the ground plane with no alpha contribution. It would be Really nice if you could eliminate environment reflection from alpha contribution, but still keep the reflection. That would make it even easier.

I think as long as I can do an action it won't be too time consuming. I can at least just run that at the end of the day or before a long meeting.

I still wonder how they achieved results in that render I put in there though. The shadows at the front look like they are on white, but you can see the reflection as well.

[dlparisi]

I still wonder how they achieved results in that render I put in there though. The shadows at the front look like they are on white, but you can see the reflection as well.

They're probably not on white but grey and it's reflecting a white light or bounce card that's above.

[andrewjohn81]

but that's where I have a problem in Max as well. I can't have my reflections as well as the shadow. If I reflect white then the shadows are completely gone where it's reflecting.

Is there a difference reflecting geometry or reflecting environment?

[dlparisi]

No, my point is that it's a balancing act. You're asking for your plane to be pure white AND reflect AND receive shadows. In order to get this your diffuse + reflect values have to equal or above one (or 255, 255, 255) but your diffuse - shadows has to be less than one.

I think this is what your looking for...


In this shot the plane has a diffuse of value of 128 grey and the reflect is 128 grey. The background is set to pure white and the direct light is just over 1. GI is on so it's getting some light from the white background as well as the direct light so you'll have to play with that in your scene. You can even have the plane material have an enviroment overide so only it relfects the white and the rest of the materials gets a hdr/sky/etc reflection...

[DaForce]

I had a really nice setup for this sort stuff. Althought im not 100% sure if shadows were involved. Pretty sure they were. But for the life of me I cant find the max file

[FlytE]

Cant you use one of the number of studio setups that are floating around? Im pretty sure they use that kind of principle for refs and shadows on a white plane?

[SonOfNimrod]

i know exactly what you mean andrew. actually it's a sort of 'format' of a lot of advertising shots nowadays it seems and i've had a previous post asking if it could be done with v-ray matte object as the ground but affect alpha with the reflection so it isolates the reflection for easier comping. in the end i had to do it in passes: shadows and reflections separately. if anyone does have an easier way of doing it, i'd be interested to know. meanwhile, here's my try.

[travistlo]

Correct me if I am wrong, But I think in the real world whenever this sort of shadow plus reflection happens, it usually because of some sort of applied finish? Like a clear coat or something.

I found its easier for me to make 2 plane objects with their own materials. one is the diffuse material (or white that accepts the shadow) the other is a coating materials that is the clear coat with a high reflection/refraction value.
Give the second plane (the clearcoat) a slight thickness, make it very reflective, and refractive. With the diffuse below it, the shadows will show on the lower plane, while the coating will reflect.

You will have to mess around with the IOR a little to control the amount of reflection, but its easier than comping. I like to have has much done by the renderer as possible.

[andrewjohn81]

great suggestion travistlo. The problem is I don't want the floor to be visible in reflections/refractions of the objects. The problem with that method is you have to make the bottom floor visible to reflections/refractions or it won't work.

We ended up comping for this one. I created a clear plane with the proper reflection amount using a vray color as white for the environment override. This ensured that the reflections where the objects were Not showed up white since there's no way to exclude the environment from reflections like you can in maya. That's an awesome option by the way. It can make comping reflections SO much easier since you can get an alpha of only the reflections you actually want.