Looking for Lamp Shade Guidance

[MegaPixel]

I'm trying to figure out wether I should fake the illumination on this lamp shade with a gradient ramp, or go a more physically accurate route and allow the bulb inside it to illuminate and push through the lamp shade, however I don't know how to set the materials up for that route. Here are some images of what I'm working with so far:

http://www.cgvisions.com/temp/lamp.jpg

http://www.cgvisions.com/temp/goal.jpg

http://www.cgvisions.com/temp/matsettings.jpg

Thanks in advance - Dave

[joconnell]

A vray light inside and the 2 sided material worked for me:

[MegaPixel]

So this would be a bad application for the VrayLightMaterial then? When you say double sided material, are you talking about the Default Max material or is there a special Vray dbl sided material I can use?

Also, is appropriate for me to model the thickness into my lamps with this technique or should I just go with a thin line approach?


Thanks for the quick response - Dave

[ene.xis]

i assume joconnell is refering to the vray2sidedmaterial!
it works gr8! the only downside i found was the "solid" shade casted by it...it can be easily avoided though!

[joconnell]

Not so - its the vray 2 sided material you get with 1.5. You make the model of the shade with no thickness to it, make the lamp material with a cloth type bump or similar and then nest this inside a vray 2 sided material. You can have different materials on each side or just use the same mat for both quite happily - you have a little colour swatch that uses grayscale values to set the amount of translucency and you're set.

[MegaPixel]

I'm still rigged up on 1.47.xx and havn't installed my 1.5RC3 yet. I was wondering why I couldn't find such a material type. The technique should be similar if I'm going for more of a frosted glass type of look right or no?

[joconnell]

For glass I'd go for blurry refractions instead with a bit of fog - the two sided mat is more for cloth, leaves and translucent surfaces rather than see through things like glass.

[ene.xis]

yeah double that!
spetially if ur stuck on 1.49 and no vray2sided mat...

[MegaPixel]

Thanks joconnel for your help. I have only one more question for you.... How do you achieve blurry refraction? I suppose I'll get rid of my light bulb since I'm going to youse a vraylight instead.

Thanks again - Dave

[MegaPixel]

http://www.cgvisions.com/temp/refractionsetup.jpg

Well, I gave the glossy refraction version a try and I'm not so sure I'm there yet. I've got this chandalier going with about 16 vraylights inside the lamps. The lamp material is supposed to be a kind of milky frosted glass which will allow some light through. I'm going to have about a dozen of these chandaliers in my next shot and so far the render times on low qual are raising some cautious eyebrows. The answer is probably in my material setup. Any thoughts?

Thanks - Dave

[Neilg]

Yeah, its the glossy refractions that cause that. Its not exactly the fastest effect going...

[joconnell]

This is true - If you're using light cache you can turn on "use light cache for glossies" to speed it up in the light cache section of the render dialog. Otherwise it's just an expensive effect to use :/

[MegaPixel]

Well, after hours of staring at my painfully slow frame buffer going nowhere, I've concluded that the glossy refraction technique can not be used on this project. I think I was getting better results with the fake gradients on the lamps.

You say you were using Vraylights in your lamp, Would using Std. Omnis or P-metric point lights be any quicker or is it strictly the refraction property of the material that is throwign the render times off? I'd love to make this work but I really don't think I can afford the rendertimes (Xeon 3.2 - 3 Gigs Ram - Vray 1.47.xx - Max


Thanks - Dave

[joconnell]

Well, refraction needs something physical to refract - so you can use an omni light but you'd have to model a bulb object and apply a vray light material to it so the light has the correct brightness. You get the benefit of not having to use area shadows via the vray light so it might be a bit quicker.