Variations of black

[everydayobjects]

For the last few weeks now my projects have required the use of various types of black materials. (Matt, textured, semi gloss and high gloss.) Initially I thought that it would be very easy to set up these materials. How wrong I was! I have had some luck with the gloss and basic matt, but I am still unable to acheive a textured black with a strong highlight. Does anyone know how to acheive a material like that? Is there a way to set the size, intensity and colour of a highlight?

Thanks, Gavin

[brandonlynne]

Re: Variations of black

I have also had the same problem with most materials. It is difficult to quickly achieve the specular roll-off that you see in other programs like Alias StudioTools, Ceinema 4D and FormZ.

Forum users have suggested that the specular in those programs is 'artificial', and thus wrong. They note that adjusting the 'highlight glossiness' value should help adjust this (by blurring the highlight), but for many situations it depends too heavily on the position of lights in the scene. This also raerely works well for black materials (as you've commented on).

Does anybody know a way to cheat and get better roll-off?

[dalomar_cg]

Re: Variations of black

In the new SR there will be the option to have per object reflection maps, which may be useful for creating this effect. The thing is that that effect is fake, and therefore simulating it in a real environment is much less quantifiable. Keep in mind to that those type of effects relate back to surfaces being rough or uneven on a very small scale. Maybe bump mapping might help you gain the type of look your going for, even if that map is a very fine, very slight noise.

[Micha_cg]

Re: Variations of black

Yes, black materials are not easy, I know. Very important is to use a gamma 2.2 output, if not, than the reflection intensity can be to low.

[dalomar_cg]

Re: Variations of black

You definitely want to use linear/gamma corrected workflow. Also because of the nature of how V-ray samples darker areas (early termination) you might be better off decreasing the Adaptive Amount, as this will make the calculations that vray does for darker areas more reliable. Don't decrease it to much though, maybe to .75-.65 as opposed to the default value of .85. That might help things a little, but it may not.

[Travis Serio_cg]

Re: Variations of black

yeah ill join this "i cant render black" club. i tried sooo hard last weekend to make a ground plane with similar properties to this vray 2 sided material image... i couldnt get the light reflections on black for anything.

[Micha_cg]

Re: Variations of black

Looks nice.

Did you use gamma 2.2 output?

[dalomar_cg]

Re: Variations of black

I believe thats a press image that Vray uses. I've seen it before, and was actually looking for it a while back. Thanks for posting it Travis...now I can sleep at night ;D I think I might see if I can recreate it via vfr... on a completely random note, I got my Rhino4 in the mail today (I'm so happy I just had to tell somebody).

[Travis Serio_cg]

Re: Variations of black

lol Glad to hear you got your Rhino 4! it's been a long long wait for all of us.

I got this image off spot 3d while reading over the online help files i came across this image as one of their samples for the 2 sided material. While i found the 2 sided material to be soo sweet and probably never usable for my industry, i did happen to take note of the black reflective ground plane with that soft warm light reflection... now that my friends got me excited. I just love renders on black reflective gp's. So i tried recreating that material with all the tricks i could come up with and I tell ya, something is just fishy with the way VFR renders black materials.

Even when not a true RGB 0,0,0 it still just doesnt do what you would "think" that it should do. I dunno, i've just never had any other render engine fight with me so much over a reflective black ground plane. I have a hard time chalking things up as "broken or bugged" vs "well it may be something to do with beta code". I think what I really need to do is knock the cob webs off of max and get V-Ray for max so that i can really compare what's going on.


here's the link

http://www.spot3d.com/vray/help/150R...vray2sided.htm

[dalomar_cg]

Re: Variations of black

Try adding a dark (15-45) color to the reflection filter. That might make it a little easier. Remember that if the gp is reflective the environment...and thats not that dark, then that won't help things either.

Glad to hear that you reading through Spot 3d. Its a great resource, and always the first place I go for answers to vray questions. I don't know how many times its going to take Joe and I posting quotes from that site for people to realize...its THE souce for vray explanations.

[Travis Serio_cg]

Re: Variations of black

I agree that site has more information than anything else you can search on the internet. It's really helped me understand each and every parameter to its fullest. The only problem is that the majority of it is theory and dependent on the scene and geometry at hand, so only knowledge, experience and many trial and errors will make you a true V-Ray expert.

I did try adjusting the reflection layer properties and colors, the environment was a standard studio hdri map that i posted in another thread. I also played with adding some point lights, spot lights, and rectangular lights using mixtures IR/LC, even tried shooting photons and qmc and still couldnt get the warm reflections off of the surface. Once i get away from black the image pulls itself together and I start getting expected results based on the parameters defined. Black seems to be a black hole. I'll give it another shot this week and see if i can get better results. Another thing that isnt helping my situation is that my alienware 7700 laptop died on me this week and home is where most of my render experiments take place. looks like ill be slummin it on one of my kids machines until i either get it fixed or replace it with something new and sassy :P

[dalomar_cg]

Re: Variations of black

I agree about spot3d in that is is more on the theory side, but it also has great examples of things too.

Here's what I've got so far with the black mats. I've got some more modeling to do with the thing in front of the paper and the shadow from inside. I also have to tweek the environment a bit more as well. Allot of the materials have very dark filters, so that seams like the way to go.

[Travis Serio_cg]

Re: Variations of black

Thats a good start and about as far as i could go with it myself.

heres one i did about a month ago on black semi-reflective the brighter areas came from the lighting, but you get the idea.





i guess what really truly baffles me about the sample render is the 2 things. 1 the fall off the reflections to all black 2) the glow from lighting (i cant recreate that at all to that degree) and 3) its hard to tell if there is a ramped back ground or perhaps dof is used to black out whats behind the objects in the far back of the scene so that the image fades to pure black.. To me it reminds me of a flamingo angular blend material going from black reflective to matte black.. but then i could actually (and probably am) making it harder than it actually is.

[Travis Serio_cg]

Re: Variations of black

my next guess is that there are some per object reflections happening on the black glossy wireframe of those pyramid shaped objects. they appear to be reflecting a white card of some sort, yet it isnt visible in the ground plane. that could also explain how they got the ubber black back ground even though the material is reflective.

[Micha_cg]

Re: Variations of black

...
Even when not a true RGB 0,0,0 it still just doesnt do what you would "think" that it should do. I dunno, i've just never had any other render engine fight with me so much over a reflective black ground plane. I have a hard time chalking things up as "broken or bugged" vs "well it may be something to do with beta code". I think what I really need to do is knock the cob webs off of max and get V-Ray for max so that i can really compare what's going on.
..

Could you explain what your problem is? Did you test it with the Rhino 3 VfR?

I got a problem with the last internal test build from some days befor. Something dosn't work with the gamma correction and reflection intensity, it cause, that a full reflective sphere dosn't show 100% of the environment. So, all metals are looking darker than expected. I havn't tested it on the new SR beta.

Or are your reflections to dark like at this thread?
http://www.asgvis.com/index.php?opti...sg5384#msg5384