View Full Version : Dielectric Tinted Glass (Blinker) Problems

Daniel Whitton
09 September 2004, 07:27 AM
I have been at this for some time now and just can't get it right. I am trying to make a shader for a car blinker tinted orange with a bump map appliead to it. So far this is my third approach using A Bump Combiner and Dielectric material. Before I tried using 3 Blend Color nodes a Phong and sampler Info, as well as using the shaders from a tutorial from Learning Maya all with no success.

So I created a very simple scene to illustrate my problem.
One cube with the Bump and Diel. And another with A Blinn Chrome which I upped the reflection limit to 10 just incase.

I am not sure how to explain the problem its just that I can not get a semi transparent Orange material with a bump map to look like a blinker.:scream:

So far this is where I am at. I have tried many different IOR settings from 1.0, 1.033, 1.2, 1.33, 1.52, 1.62, 2.0

I know crown is between 1.52-1.62 and standard glass 1.3-1.33

This is what I am trying to represent.

Please any help would be greatly appreciated.

Thanks in advance.

Dan :shrug:

09 September 2004, 08:33 AM
Can't see your images. Please check your server.

Daniel Whitton
09 September 2004, 09:11 AM
Try these, maybe, hopefully. Sorry Just bought webspace.:eek:

09 September 2004, 09:19 AM
No, sorry it's giving a DNS error :shrug:

Perhaps you can upload them here (just a temporary solution):

Daniel Whitton
09 September 2004, 09:34 AM
Removed for space.

dynamic duotone
09 September 2004, 04:17 PM
Did you try changing the orange to a orange-yellow or even a bright yellow instead of orange?

It seem like from your rendering that MR is adding red to your orange, so i figured what if you did a yellow...

Just a thought, good luck

Daniel Whitton
09 September 2004, 05:38 AM
Nope, that didn't help, it doesn't make sense to me why it would eiither, thinking that the light was difractted maybe.

Anyone one wanna take a stab at what I should do here, or should I post a btter model?

09 September 2004, 12:37 PM
I think that you should try using a shader with more of a diffuse component like normal blinn shader or even DGS. I have tried to do the same thing before but ran into the same problems. I generally use dielectric for clear or slightly tinted glass only and even then just in limited situations (works well in architectural applications or for bottles, glasses etc). When the glass is deeply coloured the dielectric always looks too dark. If you need to use dielectric then I suggest that the chrome should be reflecting some thing very bright like sky. The sample you have has the chrome reflecting a dark floor so this is not really helping the situation. The value of the should also be 1 so that the colour is all that is affected. (say the value is set to .95 then for every unit of thinkness the colour light is absorbed by .05 darkening your shader, this effect depends on the reletive scale of your model).
I have to say that dielectric being a physical shader gives you very little creative control so alot of the time you have to ask yourself whether you really want the journey or the destination, so to speak. Anyway best of luck with the rendering, BTW is it the Z4 you are doing?? looking forward to see it.

Daniel Whitton
09 September 2004, 07:30 AM
Bmcaff, Here is an update with a dgs mat. Still with an IOR of 1.33 and tranparency of .4 and diffuse of pure orange I am not getting what I want, so I need to tweek more, but it is going in the right direction.

Daniel Whitton
09 September 2004, 06:15 AM
can everyoe see the new pic or do I have to contact my web server now.

09 September 2004, 06:37 AM
its cool ;)

09 September 2004, 09:34 AM
Nice model Daniel. I would have to say that the choice of rims is probably suits the Z3 more than the Z4, they could do with being a bit more cutting edge.. Check out the official rims on BMW's site, they're not too bad. There are also a bunch of custom rims for the Z4 that are really cool.
The material for the indicator should maybe be a bit more transparent, like .85, and also the specular colour should be set to orange (high) and there can be a smaller amount of diffuse. You need to tweak untill it looks right (don't worry about the D+G+S=1 guideline). In reality the colour will be define bay the reflectivity of the chrome in the lamp and by what it's reflecting. You can cheat by adding more whiteness to the reflector (using ambient colour or pushing the spedular colour up beyond 1). If it takes a huge amount of time to get this right then you may want to consider using a photo texture instead.
Good luck..

09 September 2004, 10:23 AM
Hey man whats doing?

Looking at your frist images, i looks to me like you are on the right track what you only need todo is, im taking its a lambert go to the lambert and change your transperence to nearly white then go, to your out connection where you pluged in the MR dielectric to the Material, now go down to the Photon Checker box click it then go to your mental ray nodes go down to the photon drop down selection and find the Dielectric Photon shader and click that now, change all the settings to the exact same as your material shader and i think it should work, if it doesn't change your MR shaders COL to White and then just the color of the materal to orange and i would use a Phong material because a Car head light is not Glass, its Perspect plastic and its doesn't have as high refraction limit.


09 September 2004, 10:40 AM
looks nice so far daniel, just one question, I was told you dont have to plug your MR nodes into a lambert shader now, as maya 6 MR nodes automatically make their own shading group, is this right?



09 September 2004, 11:04 AM
That's right MunCher. However, everyhing that has MR shaders only assigned, shows up in green in the viewports.

Daniel Whitton
09 September 2004, 04:09 PM

I have taken your advice, works damn good bmcaff. I just added some bump maps to the glass which I need to work on, as well as the shader for the brakes. It's mib_ward, big network, got to lower the ambience and diffuse on it, bump it up more.

I'm thinking I'm gonna do a pass with the dirptmap shader to bring out the detail in the tires, because it's not even noticable in this render.
I don't know what to say about the compression though. Makes it look really aliased.

09 September 2004, 04:43 PM
OKaaay... looks cool Daniel.. I hope you don't mind me saying so but I think the wheels and the tyres could use some more tweaking. Although the are proportionally correct compared to the real thing (guy next door has this exact setup) they look a bit weak. I normally increase the wheel size and lower the tyre profile to get it a bit more dynamic. Car designers usually do this in sketches for the same reason. BTW I have a nice low profile tyre for download on my site (it's got fully modeled thread and grooves) so feel free to try it out.
Good luck with the completion of the project, looking forward to seeing the final product. Are you doing an animation or an illustration??


Daniel Whitton
09 September 2004, 05:14 AM
I agree about the wheels and tires. I spent alot of time searching for good reference on rims that are accurate to Z4. I plan on modeling different ones. Istill need to add some things like wipers,rear view mirror,Z4, the grille logo little stuff.

This is for my demo reel. I'm thinking a nice spin.I graduated August of 2002 would like to put this together and my other models to start job hunting.
I wanna get the shaders close and model a small set and render something close to this.
Thanks for all you help


09 September 2004, 08:17 AM
Ok, thats good news about the wheels. Check here for the offical photos

Good luck with the job search.

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