All posts relating to Maxwell Render 1.x
User avatar
By rivoli
#27970
Micha wrote: Do you mean "below 1"?
ops, sorry about that. yes, i meant below 1.
User avatar
By Thomas An.
#27971
Micha,

We know about the 0.847... but the method is incorrect; it was design for other render engines but not Maxwell.
http://www.maxwellrender.com/forum/view ... 272&#24272


(The explantion is all in the first page, ot two here; at the beginning of this thread)
http://www.maxwellrender.com/forum/view ... 06&start=0
Last edited by Thomas An. on Wed May 25, 2005 3:49 pm, edited 1 time in total.
User avatar
By Mihai
#27972
You only need to set the absolute IOR of the mediums (such as 1.51 for glass, 1.33 for water etc). You don't need to set the relative IOR of 0.85 for the glass>liquid interface since the raytracer should take care of this by itself . This is how the physics and l_glass shaders for mentalray work anyway.
User avatar
By Micha
#27973
Sorry Thomas, your method dosn't looks like Maxwell should look, for me it is a fake - two surface on the water surface - I'm not happy. I hope, this is only a temporary "best" way.
NextLimit should create some interface materials with two IORs, that would be easy physical correct.
User avatar
By Thomas An.
#27976
Micha wrote:Sorry Thomas, your method dosn't looks like Maxwell should look, for me it is a fake - two surface on the water surface - I'm not happy. I hope, this is only a temporary "best" way.
NextLimit should create some interface materials with two IORs, that would be easy physical correct.
How is it better when you have to split the glass body in two and use 0.85 in the renderman engines ? Is splitting the glass something physically correct to you ?
dosn't looks like Maxwell should look, for me it is a fake
You are looking at the photo and then the Maxwell result and you are still telling me the result is a fake ? :shock:

I guess you really mean the method of construction...
User avatar
By Hervé
#27987
he means when he poured some water into his computer, it does'nt give a glass of water... very fake..
User avatar
By Micha
#28012
Thomas,

I mean physical correct like simulations in FEM stress analyses, each boundary surface between two materials get an own property, a simple rule. Splitting the glass - it is logical if you try to think in boundary surfaces and not in volumes. For me, it is difficult to understand why I should use two surfaces at the top of the water. Also, if I think in "volumes", it is not so easy to understand. This is not the wonderful simple usage of Maxwell.
I'm curious, what the NL team will do.
User avatar
By Thomas An.
#28018
For me, it is difficult to understand why I should use two surfaces at the top of the water
Micha,

There are no "surfaces" in my method. It is only solids. One solid for the glass and one solid for the liquid.

-
User avatar
By Thomas An.
#28034
Micha wrote::shock: Do you not mean the schematic on the bottom of this page?

http://www.maxwellrender.com/forum/view ... c&start=15
Correct.
(The green surface you see there is only when you have colored glass, otherwise it is usually joined to the glass as a solid piece)
User avatar
By Mihai
#28038
That's the one, but what you see there are two solids, one inside the other. The liquid completely surrounded by glass.

Personally I don't know which method you can call more realistic because they each fake it, but in different ways. The point of this discussion is to show that currently only Thomas An's method gives correct results with Maxwell.
User avatar
By Mihai
#28055
Well here is my mentalray version. Looks very accurate as well, using the l_glass shader and glass using the "hybrid" method.

Rendertime 1 hour, setup time to get it to look a bit like the photo, around 3 hours.

It's nice to see that Maxwell has such accurate lighting distribution when comparing with the photo. The mentalray version is not as accurate, especially looking at the dark border between the box and the wall.

Image
User avatar
By Thomas An.
#28063
Rendertime 1 hour, setup time to get it to look a bit like the photo, around 3 hours
Mihai,

Thank you for investing so much time on this. 8)

The mental ray result is quite interesting, especially the fact that you accomplish all this from the hybrid-ND method (the inner engine workings are definately different)

The image looks very sharp (good contrast). Also, it is good we can actually see the bottom ridges through the base of the glass.

The caustic is not well developed; I can see it forming, but is being overwhelmed by the shadows of the straws which are a bit too strong.

You are right about the ambient lighting... it is somewhat off.

The image overall is good though and non of these points would be evident without a reference photo :) (we could be arguing for years about what looks right or not without the reference photo)

Again, thank you much for taking time to make this comparizon ! 8)
User avatar
By Thomas An.
#28064
Micha,

Maybe you can try this one using Rhinoman/AIR ? (if you have any free time these days ?)

That would be interesting to see as well.
User avatar
By Micha
#28071
Now I ask me, do I have overseen something - why is the hybrid method in maxwell wrong? In the real world, the boundary surface between two mediums is important. But why dosn't work this in Maxwell? Is the problem, that Maxwell dosn't accept ior smaller than 1? If yes, than is the hybrid method good and Maxwell need a small "bug" fix.
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