Changing Reflectivity Factor in Non-Sequential Object's Properties When Using MIRROR

  • 1 March 2020
  • 1 reply


I have a question for a CAD reflector object being used with MIRROR material property.

How do I change the reflection efficiency of the mirror so that each ray bounce takes into account this efficiency and I get a more realistic result?

I am aware of the Coating selection in the object but that applies some kind of spectrum which seems like a hassle to dig into as there are many files, I'd ideally like to just enter 0.9 for 90% efficiency or change it based on my measurements, dealing with monochrome light. The reflector will be made out of aluminum and will be polished and then either clear coat anodized or nickeless chrome plated to boost reflection.

Thank you

Best answer by David 1 March 2020, 22:37

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Hi Andrey,

You can design simple and Ideal coatings and place them in the coatings catalog and then apply them to surfaces. Look up ideal coatings in the help system. (You might want to save these in your own coatings catalog so they don't get overwritten with the next release.)

From the documentation:


will create a coating named I.75 which transmits 75% of the ray energy. Ideal coatings defined in this way transmit the specified fraction of light, and reflect the rest, independent of the ray wavelength, angle of incidence, incident material, or substrate material. Note this type of ideal coating has no absorption, and the transmission must be less than 1.0 and greater than 0.0. If the ray total internal reflects, the reflected intensity factor is assumed to be 1.0. For a more general ideal coating, see the IDEAL and IDEAL2 coating definitions which follow.


IDEAL <name> T R TIR

IDEAL coatings are defined only by three intensity coefficients: transmission, reflection, and total internal reflection. IDEAL coating names may be any user defined name up to 32 characters in length, with no special characters permitted. Note that spaces are not allowed. After the ideal coating name, the T, R, and TIR values are listed. If T+R exceeds 1.0, the values will be scaled so that T+R = 1.0. The absorption coefficient is computed automatically via A = 1.0 - R - T, to conserve energy. To make a coating that absorbs 100% of the energy, set both T and R to zero. OpticStudio assumes the phase of transmission is zero. For mirror substrates, the phase of reflection is π . For other substrates, the phase of reflection is zero if the incident index is higher than the substrate index, otherwise the phase of reflection is π. The TIR intensity is used only if the ray total internal reflects. If the TIR value is omitted, 1.0 is assumed.

Kind regards,