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Rich_Winsor

Why is Ray Tracing so hard?

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Or should I say why is it so hard to get good ray trace results?

Well I have been doing a lot of ray tracing lately and I think I can

put my finger on it now. Ray Tracing is akin to digital alchemy.

You are presented with a palate consisting of an incalculable

number of possibilities and you are tasked with finding just the

right combination of these possibilities to create that “golden”

image. I always assumed that there were lots of possible

combinations but when I ran some numbers I was flabbergasted.

Take the “Image Properties” dbx which is instrumental to all ray

traces.

 

Combinations%20Calculator-1_zps1aeguzwq.

 

Here we have 7 slider bars which each have 100 different selections

that range from 0% to 100%. Now I’m no mathematician but to me

that works out to making a selection of 7 settings out of a possible

700. So how many possible combinations are we talking about?

 

Combinations%20Calculator_zpsi8ulttrl.pn

  

1.5 x 10 to the 16th power  -  Help me out here, is that 15,000,000,000,000,000 ?

 

Holy sh$t! And you can double that number by simply selecting or

deselecting the “Use Tone Mapping” option. These of course are

global image settings and don’t even start to consider the possibilities

of changes to individual item’s characteristics which depending on

their Material Class include such as: Diffuse, Specular, Roughness,

Emissive, Transparency, Translucency, Reflection or Index of Refraction.

And then all of these possibilities can have different colors.

 

Are we getting the picture yet?  :)  That is why Ray Tracing is so hard.

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I am glad you said it, and I agree fully.  Although, its good to have lots of control on certain levels - so its a hard balance to make.

 

Perhaps a small preview window where you can see the results in a fraction of the screen size so you can make certain adjustments without needing to go back and forth with actual ray tracing?  Its not so much the options, per-se, but the fact you have to fully execute the render to see the results - then rise-repeat to correct.

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Perhaps a small preview window where you can see the results in a fraction of the screen size so you can make certain adjustments without needing to go back and forth with actual ray tracing?  Its not so much the options, per-se, but the fact you have to fully execute the render to see the results - then rise-repeat to correct.

 

 

Johnny,

 

There are options in the Ray Trace Options dbx to control the size and resolution of the Ray Trace, like Use Active Window Size, size, resolution, etc.

You can zoom in to any part of the view and only render that bit as a test at any size and resolution you want.

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Johnny,

 

There are options in the Ray Trace Options dbx to control the size and resolution of the Ray Trace, like Use Active Window Size, size, resolution, etc.

You can zoom in to any part of the view and only render that bit as a test at any size and resolution you want.

That's a very good suggestion Glenn.

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Thanks Michael, but I suspect that it won't be enough.

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I am glad you said it, and I agree fully.  Although, its good to have lots of control on certain levels - so its a hard balance to make.

 

Perhaps a small preview window where you can see the results in a fraction of the screen size so you can make certain adjustments without needing to go back and forth with actual ray tracing?  Its not so much the options, per-se, but the fact you have to fully execute the render to see the results - then rise-repeat to correct.

 

Probably stating the obvious here but you can make

adjustments in the Image Properties dbx on the fly

so to speak and they update in the ongoing ray trace.

Also as long as the ray trace window hasn't been

closed you can also make adjustments after the ray

trace has been stopped. This way you can display

2 ray traces side by side and still make adjustments

to either one of them.

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