Surfaces staying sticky

Hi Marton and all -

I am finding that facets seem to stay “sticking” when I try to turn them back to copper.
Take a facet, turn to mirror, sticking factor 1. Run simulation
Select same facet, set to “copper, rough surface scattering, 0.05”, try to re-run simulation.
If I go to “select sticking”, the facet that I returned to copper is still shown as sticking, and my flux is behaving as if it is sticking as well.

I tested both for my code and for the tutorial test surface - once turning the walls from diffuse sticking to copper, they still show up as sticking, unless you first set the sticking coefficient to zero.

I have not updated to the September release in case this is fixed, but can you verify you can recreate this and let me know if there is any way other than remembering for sure to set sticking to 0 before changing to metal?

Hello Marcy,

Physics-wise, the sticking factor is taken into account only when the relfection type is Mirror or Diffuse. It is ignored when a material is selected. This is reflected in the user interface by hiding or showing the stikcing factor textbox:
2020-09-09 09_31_50-Window
2020-09-09 09_31_55-Window

Let’s break down your issue to two problems:

1) “Select sticking” selecting facets even if they are material:
Tested and this is true, the code checks only if sticking>0, and did not check if this sticking is set to be ignored or not. One could argue that materials should also be selected (since they can be sticking surfaces, depending on photon angle and energy), however you’re right that the “select sticking” command should not depend on some GUI history and always yield the same result. I’ve fixed the code to only select sticking>0 if the facet has mirror or diffuse reflection. The fix will come in the next version.

2) Facets behaving as sticking during simulation
This would be a more serious error. So, to clarify, depending on what you set as sticking before making the facet copper, you get different results? Can you tell me what settings (low flux mode / use new reflection model) you have in Global Settings when this happens?
image
Also, are photons arriving heads-on (near perpendicular) or at a low grazing angle to the culprit facet?

I’ll test on my own then (so far I couldn’t reproduce).
Cheers, Marton