need help with lighting/reflecting workflow

[andrewjohn81]

I'm looking at something close to what the car commercials do often. They usually have these really sexy fairly white and large lights visible to reflections specifically placed on the car.

Currently I don't know of a good way, other than testing renders, to check the position and relative shape of a reflection/highlight on the surfaces without spending a bunch of time. this is especially difficult for animations.

Can anyone point me int the right direction with learning how to do this in 3D better. It's a bit more real-time with photography. I'm not sure if there's a way to show realtime reflections in max. If so I could link boxes/planes to the lights to show approximate placement for highlights and reflections in the viewport to show through the animation.

I'm just looking for a better way than I am currently doing it, which is pretty much just trial and error.

Any help is appreciated, even if it's just telling me to buy a particular book.

[Dynedain]

Look into the place highlights tool in Max

[andrewjohn81]

I know about that tool, but I'd really doesn't help that much as I can't see the highlight on the object.

Also a lot of times I want to see a large rectangular reflection of an area light, either a physical object or a vray plane, on the object. This would show, in an animation, how the highlight/reflection would fall over the surface as it is moved by.

I'm trying to find a good workflow for animating lights over an object. As well as finding out how the lights would look on the objects as they move.


Any other ideas?

[Dynedain]

I would recommend doing your lighting/reflection setup with a chrome sphere and a diffuse sphere to create your studio setup. Then after that place your object

[studioDIM]

Failing that, Dosh seems to have some nice and usable Studio HDR set.
They work fairly well in most cases.
If the worst comes to the worst, use the standard max bitmap to map them as spherical and increase tiling (more U than V, but you may need both) until the look is what you want.

Lele

[andrewjohn81]

Yeah, that's still not quite what I'm looking for. That's about like telling a photographer he can use the studio but can't really move any of the lights.

The problem with hdri's is that you can't really preview how they will look on the objects themselves. That's more what I am looking for how to do. I want to see how the reflection will look on the object itself.

I'm not rendering spheres. As such, if I view lighting and reflections on a sphere then the reflections and highlights won't be in the spot I want when I end up rendering a box instead of a sphere.


In a true studio the photographers, here at least, will have large lights that they move around the object while looking through the camera until they get Just the right reflection they are looking for. I'm not talking about little highlights either. Huge lights.
Is there a way to do that in 3d in max without having to wait for a rendering?

I know you can't expect to know the actual lighting diffuse amount because of GI, but I think it's reasonable to be able to see a simple reflection. I'm just not sure how to do it.

I'm guessing not everyone does that, but I would say the the really good guys out there have better methods that just editing an hdri for their reflections and/or lighting. I'd kinda like to hear from them if they have anything to say about their workflow and how they go about lighting things (with GI also) and using reflections.

[studioDIM]

So basically you're asking how to raytrace a reflection without raytracing it.
And an hdr (which could maybe lead to reflection mapped reflections, maybe even in realtime if you used realtime DXshaders and cubemap automatic generation) doesn't cut it.
You ARE surpassing the capabilities of my brain to understand what the solution will be, so i'll bow out, and leave it to the pros.

Lele

[andrewjohn81]

well an obvious solution there would be to use an image of the hdri temporarily so that you could see it on the objects.
I wasn't sure if there was a DX solution though. I've never used DX shaders before. I thought there might be some kind of workflow that people were using that allowed you to assign a DX shader to an object to see the reflections and highlights, then assign the original shader back to it again.

I didn't mean to insult anyone. I'm just looking to see if there are better solutions out there than trial and error. Something more realtime.

[studioDIM]

Sorry, i must have misunderstood the tone of your post.
Language issue on my part, i reckon.

I would keep lighting and reflections separate.
That is, light as normal, without caring for lights reflections at all.
Make them invisible when you're done.
Add in a studio HDR, through a standard max bitmap, so to be able to set a tiling when sperically mapping it (normally with the dosch ones isn't needed, but with others it may well be).
Assign a mockup STANDARD material to your environment objects, so to be able to have them have some generic colour and/or texture resempling the actual vray materials you'll use for the final rendering (Scene states will make this a quick job).
Switch the reflective VRay material with a standard material in the mateditor, enable the DX shader (metal Bump), turn of reflection mapping, switch back to the SCANLINE renderer, click "pick object and generate".
Select your one-mesh object (or if you have the reflective material applied to many objects, just create a simple sphere @ the origin, and pick that. then delete it), and have a cubemap generated and loaded.
Raise the reflection amount to 100% with the provided slider, and enable the DX viewport display checking "enable plugin material".
Make sure you do NOT sync the standard material, as it may not work as expected at all (and it's definitely not needed here).
Group your meshes if they are more than one piece, then parent the camera to your grouped object (better if the camera has no target, but if it has, make sure you switch it off for the time being).

Now, rotating the group rotates the camera as well, and basically counter-rotates the cubemap.
This IS realtime reflection study, as you'll be able to just render using a proper vray material and the BG HDR in question, simply by adding a "-" sign in front of the rotation angle you applied to your grouped object.
IE. if you rotated the Group by 30 degrees, simply shift the map backward by -30 degrees. Press ctrl+n when the cursor is within the U offset spinner,
and type in -30/360, and press ok.
Voila', now rendering your coatings and shiny stuff with vray will lead to exactly the same position for reflections as you decided.
While apparently lengthy, this is actually an extremely quick process, and saves a wee bit of time avoiding any render at all.
The most that may need to be rendered, is a cubemap which has different tiling (to correct for too big refs, or too sparse ones), but at small enough res it's done in near-realtime, and works exceedingly well.

Try it, and let me know how it works for you.

Lele

[Buck]

I do alot of car lighting/rendering at work. There is no quick and easy way to get it perfect. it just takes time and adjustments. Set your render to do a quick preview (noisy settings) and once you get the main scene looking good, then go to a less noisy setting and do final tweaks. After a while, you just know what to expect and it becomes easier and faster. Trial and error, that's about all there is, along with time/experience and a bit of luck

HDRs are nice, but I find that I usually need more than just an HDR. some soft area lights or cards mapped with softbox HDRs works real nice. I haven't ever used the studio HDRs that have been mentioned, but I don't think I'd like that, not much control. I much rather have my softboxes as flat HDRs that I can map on to a card.

It really helps to have a distributed rendering farm, for the speed, but I don't always get to use that either when machines are rendering other jobs.