POV-Ray Tips: Subroutines and Include Files

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POV-Ray Tips, Tricks, and Techniques	Parameter Passing?

Lee asks: Do others have this problem with POV-Ray? After defining an object, I want to change some aspect of it, without going back into the object itself or changing #declares.

Steve Demlow responds:

You can do this in a crude way using variables and #includes. Put your object that you want to create multiple instances of into a file by itself, with the aspects that you want to change represented by variables.
Then, in your main scene file, set the variables to the appropriate values and #include the object file. Repeat as needed.

For your example, put the following in "legoman.inc":

object {
    object {left_arm
        rotate left_arm_angle
    }
    object {right_arm
        rotate right_arm_angle
    }
    texture legoman_txt
    etc.
}

Then in your main scene file:

#declare left_arm_angle = <45,0,0>
#declare right_arm_angle = <45,0,0>
#declare legoman_txt = texture { ... }
#include "legoman.inc" // Instance 1 of Legoman

#declare right_arm_angle = <60,0,0>
#include "legoman.inc" // Instance 2 of Legoman

etc.

See the sphereflake and Menger sponge sample files in the POV-Ray distribution for examples of this.