Beam Exponent math?

Comments

• nonesuch00 Posts: 18,729

  June 2018

  Should cause it to become much bigger with small numbers as exponents, exponetial increases are usual bigger than linear increases

  Exponential is 2^1 = 2, 2¨2 = 4, 2^3 = 9, 2^4 = 16, 2^5 = 32, ...

  compared to linear which is just 2, 3, 4, 5, ...

  The exact forumala that beam light function will be something different those. I don't know the formula except exponent is a hint it's exponental function 
• rames44 Posts: 336

  June 2018

  I’m aware of what “exponent” means. :)

  I’m looking for something a mite more substantive (and technical) than that.
• nonesuch00 Posts: 18,729

  June 2018

  rames44 said:

  I’m aware of what “exponent” means. :)

  I’m looking for something a mite more substantive (and technical) than that

   

  Just google the mathematics of how a spotlight works then when you increase light intensity or write a tickewt to support and maybe the DS developers will give you the equation given that they know it. They might not as it's likely supplied via some 3rd party SDK..
• murgatroyd314 Posts: 1,568

  June 2018

  Digging around in the documentation center, I found the description "rate of decay from center to edge". If I were writing a function to meet that description, I'd probably go with something like this: i=c*(1-(r/R)^x), where i=intensity at selected point, c=center intensity, r=radius to selected point, R=outer radius, x=beam exponent.

  You might try a few test renders to see if the actual behaviour is consistent with that.
• nonesuch00 Posts: 18,729

  June 2018

  Video if you prefer those:

  https://www.lynda.com/Maya-tutorials/Understanding-light-decay/96718/108852-4.html
• Richard Haseltine Posts: 108,130

  June 2018

   

  nonesuch00 said:

  Video if you prefer those:

  https://www.lynda.com/Maya-tutorials/Understanding-light-decay/96718/108852-4.html

  Which is not relevant as in Iray local lights always decay with inverse square falloff. I believe it is as Murgatroyd says - decay from centre to edge of the beam - not distance falloff.
• nonesuch00 Posts: 18,729

  June 2018

  Richard Haseltine said:

   

  nonesuch00 said:

  Video if you prefer those:

  https://www.lynda.com/Maya-tutorials/Understanding-light-decay/96718/108852-4.html

  Which is not relevant as in Iray local lights always decay with inverse square falloff. I believe it is as Murgatroyd says - decay from centre to edge of the beam - not distance falloff.

  It is the same but presented differently. 

  https://www.ifa.hawaii.edu/~barnes/ASTR110L_S03/inversesquare.html

   
• Richard Haseltine Posts: 108,130

  June 2018

  nonesuch00 said:

  Richard Haseltine said:

   

  nonesuch00 said:

  Video if you prefer those:

  https://www.lynda.com/Maya-tutorials/Understanding-light-decay/96718/108852-4.html

  Which is not relevant as in Iray local lights always decay with inverse square falloff. I believe it is as Murgatroyd says - decay from centre to edge of the beam - not distance falloff.

  It is the same but presented differently. 

  https://www.ifa.hawaii.edu/~barnes/ASTR110L_S03/inversesquare.html

  No, it isn't - the beam exponent is not distance fall off, that link is again about distance fall off.