View Full Version : glass troubles

08-27-2003, 03:31 PM
hmm, didn't get any replies to this in the other forum so i'll give it a go here...

..am making a logo in glass, the glass should ge the highly polished glinty kind with lots of reflections but also still quite transparent. It should have quite hard edges to catch the light with extreme glints, rather than being to curvy, so I don't really want to subpatch.

i have been following a few glass tutorials and have given my onject an inner "air panel" the same size as the "glass" panel(refraction 1.52) but with a refraction of 1. however this gives me the very see-through, non glinty and quite dull form you see on the bottom right.

when i scale down my "air" panel slightly inside the glass panel, it gives me a thicker, nice glinty glass look, but almost too thick- you can't really see anything through it (refer the other 3 pictures).

also, if I don't subpatch, even though I've subdivided quite a bit and got smoothing turned on, you can see the edges of the polygons in places as well as getting some severe artifacts even at higher antialising settings.

does anyone know how i can avoid these without subpatching (to still keep those hard edges)? also how to make the glass look more transparent while still keeping it super-reflective and glinty?

thanks! anna

08-27-2003, 04:33 PM
Have you tried subpatch weights to get the sharpedges?

The inner air layer needs to be a different surface with rearward facing polys and only transparency should be active everything else should be off or zero except specularity for extra glints. I'd add a fresnel shader to your outer surface and you must render with raytracing on. The air layer really only needs to be smooth shifted by a very small amount so you don't get polys crashing though each other.

Hope this is of some help


08-28-2003, 06:08 PM
my experience is that the whole air surface thing kind of works, but yeilds results like you mentioned... I usually opt to make the actual surface more refractive... until it looks good.

Other folks here can flame me, but I always do exactly what it takes to make the sohot look right... and nothing more.... I don't care if it's mathmatically incorrect....

08-28-2003, 06:50 PM
Does this mean that we now have 3 girls using LW?? :)

08-28-2003, 08:52 PM
ha ha yeah looks like it
thanks for your feedback, i will try again with those changes.
also, the scene i've got this in is quite dark and
has volumetric lights which enhances the glass look- ultimately it's going to go into a quite light scene- even a sky background-
anyone got any tips on good lightling for glass?
I'm a bit at sea with lighting and texturing, modeling
and animation is my forte!

08-29-2003, 01:19 AM
3DGirl - I was never good at maths in high school, but can't you write that as DDD Girl? Just a thought. I'm sure you would get a lot more help from male users.

Sorry I cant help with the glass problem, I'm a newbie member.

08-29-2003, 01:53 AM
Uh OK ;)

You could play around with the smoothing angle for the glass surface... You could have 2 copies of the same glass surface and change the smoothing angle on each and apply it to polygons where needed...

How are your specularity and reflection set up... they should be high with a high glossiness for your highlights...

08-29-2003, 01:55 PM
is this the sort of thing you had in mind with the glass?


08-29-2003, 01:57 PM
or this one ( I couldn't work out how to attach more than one image at a time)



08-31-2003, 03:42 PM
uhhh yes that's lovely!

can you share your settings? did you use "air" ploygons? what did you do for the glints on the edges?

09-01-2003, 01:41 AM
To 3dgirl

If you send an email to me I'm [email protected] then I can send you the scene file and the model and images so you can check em out and do as you will with. I'd attach em here but I don't have stuffit so I can't zip stufff and I'd just mess it up anyway.
So drop me a line and I'll email you the files.



09-01-2003, 02:04 AM

There is a really good tutorial on modelling a bottle of jack daniels. It covers the texturing also, and this had really good glass. I hate to say it, but I can't seem to find where this tutorial is. I'm hoping someone else may be able to point it out.

It's just that it's late here and I'm tired of looking.

A couple of tips, though:
1. glass refraction=1.33
2. air refraction=1.03
3. for air, copy glass, paste, flip polys, and give a different texture

Another thing that may work is set a gradient for refractive index on the the reflection of the glass. It reflects more at angles facing away from the camera.

good luck.


09-01-2003, 03:53 PM
thanks marvin- yeah I've actually done that jack daniels tutorial,
it's quite good- here's the link if anyone's interested:


09-01-2003, 09:16 PM

I got the link for the Jack Daniels tutorial from someone named 3dgirl. Here it is: http://www.liquid-arts.de/techniques.htm

(It seemed funny at the time).

Does that mean these settings don't work for what you are trying to do? I haven't actually done this tutorial myself, but I've made glass dozens of times. I use similar settings.


Graham Nichols
09-02-2003, 10:02 AM

Does anyone please know what modeling technique was used to construct the screw-thread on the neck of the Jack Daniels bottle?

best, Graham