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View Full Version : Glass !! Nooooooooooooo !



davie563
11-29-2004, 03:55 PM
Hi, im trying to create a nice pic of a old style milk-shake glass, and am trying to get the scene right :p

the glass is killing me, i got a HDRI map on it, but it just dosent seem shinny, anybody know good tuts for glass, or even some tips for this type of stuff...... i mean are HDRI maps the way to go to make it look real ??

looking forward to your reply :D

here is a wee test render ( and i mean weee, took ages to render with Caustics on and stuff LOL ) im not trying radiosity, well not till the final render anyways :p

davie563
11-29-2004, 04:19 PM
here is a test render i took, when i put my glass into 1 of the preset scenes free with lightwave, i just wanted to see what it looks like,

what u think, and anybody got tips :p

Silkrooster
11-29-2004, 05:26 PM
Check out http://www.robinwood.com/Catalog/Technical/LightwaveTuts/LWPacks/LWGlass/LWGlass-1.html and http://www.geocities.com/CollegePark/9315/lw/tip4.htm
Plus there are several threads on this forum about glass.
What you can do is check out the presets and see how they work, in the surface editor. What transparancy they use, how much diffusion, what shaders are used, and what's the color filter set at. Check light properties like caustics and which light type your using, distant lights do not use caustics, but spot lights do.
Change your background, to a floor and backwall with textures so you can see if the glass is working or not.
Hope some of this helps.
Silk

Nigel Baker
11-30-2004, 06:47 AM
Hello Davie,
Remember glass reflects its environment so a good little trick to help to building the illusion is to place two or three polygons in the scene that are not seen by the Camera and bring up their luminosity and difussion to act as reflecting source lights like in a photo shoot and try that.

Look at other scenes on the LW CD to see how others are threating their scenes.

Another source of help is to check out http://www.the-worms-of-art.com/ for their PShelf - Glass collection.


All the best..

Darth Mole
11-30-2004, 10:43 AM
You might also try doing the caustics as a separate pass - I find they do tend to look overbright; you could just render them on a solid black background and then Screen them in using Photoshop. Or something.

davie563
11-30-2004, 02:50 PM
another really anoying thing, is that it is really hard to get a cool, shadow with glass, because the light just goes straight through it, thx for the links, ill check them out right now, and get back 2 you with updates ;p

cheers

davie563
12-07-2004, 10:27 AM
Hi, i started my vase again,

what u think ? i quite like this render, but i was just wondering if anybody could give me tips for making it look more photoreal, i have an HDRI image with Anti-A on medium and Radiosity and caustics on. but i dont know how to get those really cool shadows that show up like transparent red just like the vase itself.... :mad:

cheers in advance :D

davie563
12-07-2004, 05:22 PM
No tips ?? :eek:

lol, i know u got loads ;)

Silkrooster
12-07-2004, 08:56 PM
Something I recently figured out, is that the main light needs to be raytraced for the caustics to work. All the rest of your lights can be shadow mapped for softer shadows. Check out my snowglobe over on the wip forum. You will see how the light is reflected off the back wall. For this to happen, raytracing is required.
Silk

Silkrooster
12-07-2004, 10:23 PM
So far the only way I have been able to render an object with colored shadows is to turn off caustics.
Silk

Avebeno
12-13-2004, 03:37 PM
I'd suggest you place the glass on a birghter surface, so you have something to really reflect in the glass.