car shader - flakes, sparkle ?

[bernhard]

Hello everybody,

I would like to create a carshader with flakes / sparkle in it.
I tried several versions, from noise, to sparkle maps, bitmaps and normal maps, but not one of the shader gives me the result I am looking for.

would someone like to help me and work it out ?

appreciate every little help, suggestion and hint.

thank you,
bernhard

[Morbid Angel]

have you looked here?
http://www.vray-materials.de/all_materials.php?mat=1915

[bernhard]

yep...

yep, thank you for your fast reply...

I tried several versions from posted materials on vray-materials.de
All the flake or sparkle versions I found work with a bump or normal map.

For some reason, it works on a small object like a teapot, but on the car I couldn't get the right look.

Tiling issues, sometimes it burnes out... and some shaders just use low samples to prodcue kind of flakes - but so you can't really control the size - it's just random.

Hmm.. I would love to work it out... but all my tries so far, didn't look good - or better, it looked terrible...

I will try the one you have linked to, and post the result on a simple geometry...

thx a lot,
bernhard

[Morbid Angel]

if you cant get it right, that means probably the scale of the texture in world space is off on your actual model. Further your model must have some form of uv's. Or it can be generated by 3d noise. Either way, if you would have a custom shader such as mr carpaint shader it would follow the same principal more or less.

[simmsimaging]

I did not find any of the shaders from that site worked too well for me either - at least not consistently.

I would suggest creating a sparkle/fleck map and using that to mix in a mirror-like material into a carpaint type base material using a VrayBlend mat. That way it will react to light more realistically, but you have to use realistic lighting approaches (HDRI Domes, area lights and/or reflector planes etc.) It did not work as well with Max lights, but I don't usually use that approach.

b

[bernhard]

hmm..

Thank you Dmitry & Brett.

Well, here is a quick render, so you can see what I mean:


The noise, flakes or sparkle is everywhere. Especially on the hood, you can see a very strong noise... the shader itself get's to black as well.

Usually, when you look at at carshader with the flakes, you can't see it everywhere, just on some specific highlights.

This would be my goal, to get as realistic as possible.

For the test scene I used a simple HDRI.
Here is the scene file for download:
http://www.helpfamily.us.tt/carshader_flakes_002.max (max2009)

@Dmitry:
I checked of course the mapping, I also tried different UVW maps, as example the flakes on map channel 2, etc... but couldn't really find a good way to get the specific look.


@Brett:
thx, I tried a VrayBlend with a base shader and on top of it with the flake reflection.
result was very bad...

I also thought, maybe it works like that:
The sparkles should be the reflective part... so I created a fall off map, and used only in the highlights a speckle map... uff.. but... again, I was defeated by myself...


after trieng a lot of different versions.. I thought it's time to post for help...

bernhard

[simmsimaging]

I will try and dig up the material I used before, but I don't think it was much better than what you have there really. Hopefully one of the real material experts can chip in on it.

b

[simmsimaging]

Here are two renders of the one I had done. This is using a variation of the sample scene that I use, so it's not quite the same lighting setup. It's just an HDRI in a vray dome light though, nothing fancy, just different.

This has two flake layers using the same fleck map, just offset slightly for one. The one has a blue tinted reflection colour, the other is almost white, but otherwise it's basically as I described before.

Below that is a snap of a metallic car hood that I used for reference. It's sitting in a more contrasty lighting environment. A bit of Photoshop work would match them even better, but I think I got close enough for what I needed.

b

[Morbid Angel]

I would have to say that it would be nearly impossible to do flakes like that using conventional anti-aliasing and filtering methods. These methods are designed to smooth out and interpolate pixels.
What seems to be pretty clear to me, is you may need to use a multi pass approach. Where you will separate base coat, flakes, and shine with passes, and render the flakes without antialiasing and filtering, then composite them via special mattes etc.
This seems to me a logical way of doing a really advanced car paint.

[vlado]

Peter did a very good carpaint shader recently, I have to ask what were the settings... I think he used a cellular texture for the flakes.

Best regards,
Vlado

[jacksc02]

In my experience a carpaint shader is only as good as the UVs on the base mesh. So spending time on the UVs is very important.

[bernhard]

hmmm..

Thank you for all your participation, that's really awesome.


@Vlad & Brett:
would be cool if you could post your sample mats, so I can run more tests.


@jacksc02:
I agree, the UVW's have to be nailed down first... I was thinking to unrwap a specific car, completly, every single part in order to get a nice uvw template. The only bad side is, that if you texture the whole care with the flakes and spread it out nicely, you do have to make that very time consuming work on every new car.

to avoid that, I was thinking to get a kind of procedural shader - well, especially for the flakes.


@Dmitry:
hmm, really nice idea.. the only question is how you would like to start doing that and how you would like to make the composition ?


It's not as easy to get this specifc look, and all knowledge and tricks must put together in order to get a real master piece.


THANK YOU ALL for your great ideas, comments and suggestions,
I really appreciate that much,

bernhard

[simmsimaging]

PM me and I will send you a link.

b

[simmsimaging]

I see you already did - I'll send you a PM with the link when I get a chance to post the mat.

b

[bernhard]

some more tests...

ok, here are some more tests...




as you can see, it doesnt' really look very good...

the flakes are not really to control, when used with low sample settings and glossy reflections...

more or less the shader on vray-materials is a fake, maybe usable as a christmas glitter shader on a christmas sphere - I guess for that it's perfect but not really to use for a car body.

I will keep going and make more tests...

@vlado:
did you already get the chance to get the shader you've mentioned earlier ?


thx a lot for every idea and help,
bernhard