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Blender's renderer and external renderer export

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Jacks_Depression
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Results will very?

Post by Jacks_Depression » Mon Jan 09, 2006 3:38 am

I am new to blender and Yafray but not 3D. I used to work with Swift 3D, but dont hold that aginst me. :)

So explain this to me... why do the rendering engins differ so greatly?
Example...
Blender
Yafray

Why is it that Blender doesn't cast shadows and Yafray doesnt allow any light though the transparent meterial?
You can see a little light in the Yafray, that is just a support for the main light source.
- Bryan

LetterRip
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Post by LetterRip » Mon Jan 09, 2006 8:41 am

You just need to change the settings of the particular lighting etc you are using - see the lighting and yafray section of the manual.

LetterRip

Jacks_Depression
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Post by Jacks_Depression » Mon Jan 09, 2006 6:29 pm

I'm not asking how to solve it. I'm sure I can figure that out.

I would think the information sent to the rendering engine would be very specific and not very. Then the rendering engine would use its own method to display what it is told...
- Bryan

bannerboy
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Post by bannerboy » Mon Jan 23, 2006 10:51 pm

the main reason is that blender and YafRay are completely different engines, developed differently, and by different people. the blender internal render engine is the same render engine as has always been in blender, but yafray export support is relatively new. when you render with yafray you are exporting into a different format and rendering with a different render engine. the way that the two render engines handle light, reflection, shadows, etc. is different for the two render engines, and those internal differences give different outputs.

Toon_Scheur
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Post by Toon_Scheur » Wed Jan 25, 2006 7:44 pm

I think Jack_Depression's question is more of a general nature.

The mathical methods to render a 3D scene is a vast area that is constantly evolving. There are many many mathematical models of how to 'render' something. I guess the ultimate goal is photorealism. Although light is 'just' a couple of photons bouncing around, the way it interacts with materials and medium is very complex.

Blender's render engine is what we call a scanline render engine. What is basically does is that all pixels are like little windows on your screen. The render engine looks through that pixel, figure out what is out there in the 3D world (there is a lot of sorting done because of objects could be in front of each other) and assing a colour to that pixel based on the shading, texture, lighting etc on the particular spot. This method is very fast, but not realistic. Light behaves more strangely than that.

Yafray is a G.I. renderer, which means that it takes indirect illumination into account. In the real world objects keeps illuminating eachother. Some more than others. Yafray uses path tracing if I'm not mistaken. We could keep talking hours and hours about what a render engine is and what set it appart from others. To make a long story short: different mathematics, Yafray uses a near photorealistic render method that comes with a huge speed penalty. Even when using the same method, the same rendering on other software could look different. There are always error margins versus accuracy where the speed/quality tradeoff is influenced (amongst others).

Lynx3d
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Post by Lynx3d » Thu Jan 26, 2006 1:45 pm

Well yafray can render without GI too (and yafray also can do photon mapping + final gather...)

But the main difference here might be that Yafray does only support light sources with inverse square falloff, because all other types are not physically plausible and therefore make photon mapping impossible.

Transparent non-refrating media are not yet supported either, unless you do it with photon lights as with refracting media.

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