Am 14.12.2010 10:42, schrieb optima:

> Thanks for the answers. To make what I mean more clear by differences I include
> the path to my gallery
> http://www.optimadekor.com/galeri/mutfak_program_optima.htm

Image #1 appears overly bright to me; the ceiling appears to have an 
"ambient" term (or, in case it was rendered with an up-to-date 3.7 beta, 
an "emission" term); same with the fruit.

Geometry looks fairly sophisticated, with beveled edges and stuff 
(though the geometry of the lower shelf in the corner seems incomplete, 
see the shadow), and radiosty settings seem fairly good.

You might try improving on the diffuse reflections. Focal blur might be 
a good idea for that, because it can do a fairly good antialiasing.


#2 has the same problems with the ceiling as #1; wall tiles texture 
could be improved (not enough bump, maybe too much ambient), floor tiles 
look much better. Doors texture shows that you're already using 
sophisticated texturing features, but I think the scale is wrong, and 
the bump mapping maybe a bit too strong. Metal surfaces appear somewhat 
too bright, maybe too much diffuse.


#3 ceiling is much better, but shows that you need better radiosity 
settings. Wall tiles seem to use ambient once again. Glass doors might 
look more convincing with stronger reflection (try "reflection 0.0 1.0 
fresnel" and "ior 1.5"). The lower door of the fridge appear "decal-ish" 
somehow.


#4 appears to use ambient on the ceiling again, and maybe also on the 
walls. The doors look too flat for some reason I cannot identify; 
something about the reflection doesn't seem quite right. The glass doors 
look like they could use more reflection again (see above). The pot on 
the very top shelf on the right is the only convincing metal I've seen 
in your shots so far (and is very good at that), so have a closer look 
at that one.


I don't think we need to discuss #5 and following - you just can't get 
convincing results without radiosity (or, to use the more general term, 
"global illumination"; radiosity is just one out of various algorithms 
to compute that).


So all in all: Yes, there's still room for improvement in your images 
with POV-Ray.

In general, many of your textures appear to be using ambient; this is ok 
for preview renders without radiosity, but it is an absolute no-go for 
realistic radiosity renders; if you're using radiosity, make sure you 
also use "ambient_light 0" to disable the ambient in all textures (or, 
alternatively, use an up-to-date 3.7 beta and make sure you have a 
"#version 3.7" statement in your scene).

You also seem to have problems getting metal textures to look right; 
maybe this has to do with ambient as well, but there may be other 
reasons. Look at the pot I mentioned, because its metal texture looks 
really good. Unfortunately, POV-Ray is currently rather poor for 
modelling dull metal: You really need blurred reflection to make that 
look convincing, the "diffuse" term is an insufficient substitute. At 
present, that means you'll need to use some micro- or macronormals 
approach. (My personal favorite approach is to use a single-layer 
texture with a very small-scaled normals bump, and use high 
anti-aliasing using AA or focal blur. Other people prefer a 
multi-layered approach, which does not require anti-aliasing but gets 
very costly for rays reflected multiple times.)

Speaking of reflection: When you're working with mirrors, make sure to 
model a complete room so that the mirror doesn't just reflect a uniform 
background. You can mark the corresponding geometry as "no_image" if it 
would otherwise obstruct the camera.

Speaking of mirrors: The second-to-last image (non-radiosity) suffers 
from the reflected wall being brighter than the non-reflected wall, 
which is obviously physical nonsense. Photons may help in such cases.

And finally, you may also want to look at your glass textures; I'm not 
exactly sure how they will look best, but I'd recommend trying 
"reflection 0.0 1.0 fresnel" and an IOR fitting for window glass 
(something roughly around 1.5). Also make sure that the glass has no (or 
very little) diffuse.

Occasionally you may be struggling to achieve some particularly vivid 
colors. In such cases, dare to set some color components to /negative/ 
values. While counterintuitive at first, such values /can/ make sense 
physically.

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