What are the Functions of Blender Internal and Cycles?

I am new to Blender and it’s modes of rendering. This is not meant to get into a discussion about render speeds or comparing how the 2 modes render a given scene. This is about the functions of the 2 modes and what we should expect when choosing either mode for rendering.

I am coming from years of using Sketchup and Kerkythea. I really love Kerkythea render engine because of the endless options I have when dealing with textures and making materials (not to mention it is also free and very fast). I like physics based render engines that give me less “faking” to worry about. So when Cycles was introduced in Blender, I was impressed and it nudged me to want to learn Blender more.

Now that I finally got a few projects going in Blender, I will admit I did not take Blender Internal render as seriously as Cycles…until I attempted to redo the realistic earth tutorial by Andrew Price in cycles thinking I would be able to do that ColorRamp trick with the night lighting. Someone here in the forums informed me about a limitation in Cycles that would not allow that trick. So now even though I think Cycles is a very good render medium, I feel like I ran into one of its limitations. I feel like I can be more creative with textures and materials in BI than I can with Cycles as far as shader options go for the simple fact that an effect I am going for that is possible in BI is not possible with Cycles. And what BI lacks that Cycles have as far as visual results go is a matter of convenience.

I just want to be pointed in the right direction to understand both render modes of Blender. Is there a chart that has side by side comparisons of what each one can do functionally (aside from CUDA and lighting advantages)? I would hate to be knees deep in a project to find out I chose the wrong render mode and then have to go digging into the node editor to pull plugs. Are there any future plans to improve shader options in Cycles?

One thing you need to know about Cycles is that it does everything in a path-tracing environment. This sort of method excels at physically-based materials and lighting, but it’s sample > evaluate > sample methodology means that you are not able to use a shader as a driver for a value in another shader like you can in BI (ie. using the brightness of the diffuse shading to determine where a texture goes).

For it to do what you want, Cycles will need to use a different tactic that would allow for multiple layers of evaluation per-pass, it’s very possible though that this will be quite difficult to do without removing the unbiased and progressive nature of Cycles, which in turn would disappoint a lot of users because it really extremely helpful to just let a render go until you feel the noise is low enough or enough has been removed that you can remove the rest in a 2D program (which completely takes the guesswork out of just how many samples you would need for the final image).

When I say guesswork and all that, that’s something you go through a lot when working with BI, when rendering with BI, you will not actually see the samples accumulate and the noise being reduced, instead, you have to wait until the pixels are done being rendered and you see the final result. Cycles also has the advantage in that there are no pre-processing stages like with SSS, in BI, you might have to go through several pre-processing steps which might take half an hour or more before you actually get to see what the final image will start to look like, Cycles meanwhile skips all of that and allows you to get an idea of the final result immediately.

Thanks for your detailed answer Ace. Sorry I took so long to reply. I guess I’m better off just using BI for this project. I plan on doing an animation if the planet slowly rotating. I will continue to experiment and see what works best for me before I go too deep in serious projects.

I’ve been using cycles for over 40 days, and I think it renders more realistically than internal. However, cycles does not have the volumetric lighting you will need for your clouds. With a lot of extra effort, you can use the compositor to get the best of both engines.

BI is a dump raytracer with crippled GI functions but extremely fast scan line rendering and perfect for graphic like motion designs.

Cycles is a pretty impressive path-tracer that uses the GPU and has a fantastic node based material mixer.

You stated that you used Kerkythea - so why dont you buy the new finale version of Thea? It is a fantastic engine fast has the same render modes as Kerky and uses the GPU now as well.

I own it and to be honest it beats Cycles in many areas for realism but it is not as flexible with materials because it is made more for object and architecture rendering needs.