How to create a computer screen in HB surface for Radiance

[David1]

I was trying to create a glowing surface in the model, which I learned that we could call from HB Radiance library to assign the property to a created HB surface. Also, we could create our own Radiance material by giving it RGB values.
I did check the Radiance tutorial it also shows the glowing material to use, but I wasn’t sure what would be the typical values to use. And also how to check which side it will be glowing to, and also will it be glowing all the time? Or it will glow on both sides which sounds not reasonable.
The following is from the Radiance tutorial website:

Glow
Glow is used for surfaces that are self-luminous, but limited in their effect. In addition to the radiance value, a maximum radius for shadow testing is given:
mod glow id
0
0
4 red green blue maxrad
If maxrad is zero, then the surface will never be tested for shadow, although it may participate in an interreflection calculation. If maxrad is negative, then the surface will never contribute to scene illumination. Glow sources will never illuminate objects on the other side of an illum surface. This provides a convenient way to illuminate local light fixture geometry without overlighting nearby objects

Any suggested values to use for simulation, especially for the maxrad value could 0 be for a computer screen?? And also how to check which side it glows later on?

[sarith]

@David1

I did check the Radiance tutorial it also shows the glowing material to use, but I wasn’t sure what would be the typical values to use. And also how to check which side it will be glowing to, and also will it be glowing all the time? Or it will glow on both sides which sounds not reasonable.

The glowing direction will be the one to which the surface-normal of the polygon is facing (i.e. the polygon to which you will apply the glow material to).

@David1

And also will it be glowing all the time?

Unless you run two different simulations with different values of glow materials, yes, it will be glowing all the time. Radiance renders, or calculates illuminance for, a point-in-time so everything is fixed for a particular simulation.

@David1

Any suggested values to use for simulation, especially for the maxrad value could 0 be for a computer screen?? And also how to check which side it glows later on?

If you want to deep dive into the subject and get a photorealistic rendering, I would suggest starting with Matiu Carr’s nearly 30 year old (but still 100% applicable) write-up on the subject. If you just want to get stuff to work, I would suggest looking through the model files shared by Greg here. A more worked out example, which was developed through the files shared by Greg, has been documented by @Moult here.

Regards,
Sarith