just an idea

[eman7613]

I do not know how plausible this is, but i was thinking to myself, "it woudl be bloody hard to render water on a windshield" there would be just too many changes in teh shape of the material for it to be practicle to render, let alone model. So i was wondering, is it thesible to create a special displacement map option that instead off just moving the polygons of the objects, also uses a separate material for just those polygons?

If this could be done, you could have a sheet of glass (ie: car window) and have a 2d copy of the glass placed just above it. with this special displacement map and an alpha map you could easily (well more so) create watter goign down the side of anything.

[Kachu]

Have you thought about using blenders water simulator?
You can use it to simulate the water and then convert the bobj to a hard model for export.

The hardest part would be getting the water to fall the way you want and getting it to stick to the glass correctly.

Here are some Blender water simulator examples
http://www.vestaldesign.com/blog/wp-con ... 703434.png
http://www.youtube.com/watch?v=-AiLyQWXjIg

[CTZn]

Maybe ther is a simpler way, wich would be to have twice the object at the same spot (this may be the trickiest part for Indigo itself), one being 100% glass, the other one being a blend between water and null material. You would use a map with shaded droplets for bump, the other one based on the same map but with no shades to blend the two mats. Got it ? This is theorical, and a fake of course, it won't work for profile/close-ups

[eman7613]

the idea behind making a poly with an alpha and displacement map is that you dont have to play with a lot of paramaters and fidgit around with fluid sim. Also, its easier to do on machines that just dont have the cpu power to run fluid sim a number of times to get it right.

as far as i know, the diffrece between bumpmaping & displacement mapping is the bump is an ilusions, while displacement actually moves the vertices's of the poly. If my understanding is correct, bump mapping wouldn't give the same visual affectt caused by the minute differences in the amount of water on the surface of a apne of glass or something.

[Aardbei]

But normal maps would


(well, almost)

[CTZn]

as far as i know, the diffrece between bumpmaping & displacement mapping is the bump is an ilusions, while displacement actually moves the vertices's of the poly.

Well, that's correct and that's why I'm saying it's a "fake"

In the scenario you depicted, there will be no benefit from using normal maps prior to bump maps, because drops of water running down a planar surface show no slopes, i.e. the normals will almost never point toward the surface itself. If I understand you right eman7613, what you ask for is pure displacement mapping. That involves, as you said, vertices to be displaced, thus a very dense mesh, or a tesselating algorithm. This is kind of tricky to set up (how many times should the surface be subdivided, regarding what parameters etc), once it has been implemented in the rendering system tho wich is another story.

When you ask for an alpha map, well, Indigo can already blend materials using a bitmap and in fact, just like you said Didn't you know that ? That is not documented and in fact I don't know how to use it but the code is somewhere in these forums...

Indeed displacement mapping and bump mapping are different processes, but right now you can do that water running down a windshield with Indigo, that was my point. Sorry if I'm totally OT.

Another caveheat with bump mapping is that two surfaces will be juxtaposed, and AFAIK no rendering engine can discriminate wich one should be rendered prior to the other thus corrupts display.

Again eman7613, please correct me if I'm wrong but you ask just for a displacement feature aren't you ?

[eman7613]

wups, now that i actualy stop and think about it just displacment maping WOULD do it... lol at 2 am it didnt seem that way >.>

[CTZn]

I'm not the one who would blame you then, eman

Cheers

[zsouthboy]

If you honestly wanted to do something like this, I beleive a blend between the "water + glass" material and plain glass, combined with a bump map, would work.

The perfect physical correctness isn't going to happen anyway, without modeling the water, so that would be a "good enough" solution.