Le 13-09-22 15:46, Warp a écrit :
> IanDean <nomail@nomail> wrote:
>> My issue is that when intersecting my current single array with a box, the
>> cylinder ends become black, they don't retain the color of the cylinders if the
>> box wasn't there. I've tried all combinations of intersection and difference
>
> If you are applying an intersection between a pre-textured object and
> another object, and you want for the cut parts to have the texture of
> the first object, you have to use the 'cutaway_textures' keyword in
> the intersection.
>
>> 2) How can I do this rendering, but with a white background? I don't see
>> anything when I make it so.
>
> Emissive media can only add to the color behind it, never subtract
> from it. Therefore any emissive media against a fully white background
> will become white.
>
> You'll have to add some absorbing component to the media if you want
> it to be seen against a white background.
>

I've done some test and got unexpected results.

If I apply "boxtexture" to the intersection as a whole, or apply it to 
the cuting box, or use cutaway_textures, the end of the rods become 
invisible with no media showing.

Adding hollow to the box or the intersection don't work.

The following Do work:

union{
	object{waveguide3D rotate<0,0,0>}
	box{<-10,2,-10> <10,-1,10>}
	box{<-10,8,-10> <10,11,10>}
	texture { boxtexture }
	rotate -7*y}

The media is suppressed inside the 2 non-hollow boxes and the media 
correctly show through the top of the cylinders.

Also, I think that it's preferable to change the beggining of the 
colour_map as follow:
       [0 rgb 0]
       [0.001  color r_violet1 transmit 0.98]


Next, to get MUCH faster results, in the media definition, remove 
intervals 10 and use the default value of 1.
Increase samples around 40 to 60. Note that the second value is silently 
ignored if present.
intervals 1 samples 100 is usualy faster than intervals 10 samples 1, 
10, with the "10" been ignored, for 10 times as many samples.
You can also remove confidence and variance.



Alain

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