Ray-Tracing : 3032


CAD / Ray-Tracing / 3032

How would you do it? —Larry Pieniazek

A long time ago, Jeroen kindly rendered this image for me in POVRay (URL) the source got lost. Now I need it much much larger so I'm trying to recreate it. I am all the way there (all models positioned right, etc) except for the lighting/shadows. (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Kevin L. Clague

(...) Hi Larry, I'm not much of a POV expert, but it looks to me like Jeroen used a single light source (I only see one shadow per model). I'd guess the light source is very far away (to simulate sunlight) because all the shadows cast proportionate (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Anders Isaksson

(...) You can use many lights, and still have a single shadow by making all lights but one 'shadowless' (a modifier to the POV light description). I often put a (not too bright) shadowless light at the same position as the camera, to make sure (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) How bright is "not too bright"? These lights don't obey the r**2 law like real lights do, right? I noticed that if I have several rgb<1,1,1> lights the scene seems "overilluminated" Do you use .5 or so for the not too bright ones? (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Anders Isaksson

(...) Actually, the sum of *all* your lights should not be too much over <1,1,1> as some parts of the image may be saturated. I usually use 0.5-0.7 for the *brightest* light, and 0.1-0.3 for filler lights. Remember it's easy to modify light (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) I am considering using parallel instead of a light source that's very far away... I don't think Jeroen used "parallel" for his source(s) because the shadow angles are steeper in the foreground. (this will be less pronounced with light sources (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Anders Isaksson

(...) If I understand it correctly, 'ambient' is what you see if all lights are off. I usually turn this down very low (zero). 'Diffuse' is reflected light from other surfaces, you'd want quite a lot of that. (...) Yes, I think the default (...) (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) Hi Anders! I sent a note requesting it to the address shown in your post, is it still correct? Mine is, so you can use that one to send it. I really like the way that image looks (as well as the next one in the Brickshelf gallery) so would be (...) (13 years ago, 3-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Anders Isaksson

(...) Received and replied with a zip of the .pov file and accompanying images. The settings for the brighter render is probably in the out-commented light settings in the .pov file (and without radiosity) - I don't know for sure, I fiddled so much (...) (13 years ago, 3-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Scott Wardlaw

It looks to me like each model / row of models was rendered in POV-Ray individually and then PhotoShopped together. Probably removed any reflections when combined on to one image. Scott (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) I'm 99++% certain that's not the case, given the input data Jeroen was able to recover for me. I think removing reflections would be a lot of work, better to change the properties of the surface to get them not to happen. (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Orion Pobursky

(...) Looking at the lighting, I'm pretty sure he used radiosity and prolly his FastRad library. I might still have a copy lemme poke around. -Orion (13 years ago, 2-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Michael Horvath

(...) FastRad is a good choice for this scene. I would also use a parallel camera and lights. Mike (13 years ago, 22-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) I am using an orthographic camera because I don't want perspective at all. I didn't try parallel lights. (there are such? or do you mean area?) That may be what I need to correct the shading differences. One thing I'm still chasing is that I (...) (13 years ago, 22-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Michael Horvath

(...) Yes, there are parallel lights that work just like orthographic cameras. Check the docs. This way you will get uniform lighting on every object in the scene. Mike (13 years ago, 24-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Timothy Gould

(...) --snip-- (...) To take a stab at it: * The light is very high. You'll have to tweak its angle. * If you use an area_light you'll probably get the soft shadow edges * Reflection is turned off or very low * The ground has a fairly high ambience, (...) (13 years ago, 3-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Larry Pieniazek

(...) Thanks for the tips... I used LDView to conver, and got a render that's much closer to the original. However I've got one niggling difference that's bugging me. The transparent colors seem "lighter" somehow, meaning that the interiors of (...) (13 years ago, 5-Jun-11, to lugnet.cad.ray)

Re: How would you do it? —Anders Isaksson

(...) Could be an effect of the 'ambient' value for the transparent colors. If you look at the pov file I sent you, you can see that I have used the following for color47: #declare Color47 = #if (version >= 3.1) material { #end texture { pigment { (...) (13 years ago, 5-Jun-11, to lugnet.cad.ray)