Problems achieving clean render with striplights

[tricky]

A scene I am working on has quite a few hidden/recessed/coffer striplights. The path for these lights has been brought in from Autocad and then the sweep modifier has been used to give them a square profile of 30x30mm.

I am then using a VrayMeshLight on this geometry.

The renders I have achieved so far are quite dirty, despite having moderate render settings.

Adaptive DMC sampler at min=1, max=12 and Clr Thresh at 0.005
GI Primary = Brute Force at 8 Subdivs
GI Secondary = LC at 1000 Subdivs

Here is a work-in-progress render to show what I mean:



Is there a better way to get clean results?

[LarsSonparsson]

Isn't the Brute Force 8 subdiv quite low?
What about the light subdivs?

[tricky]

I've tried upping lighting subdiv to 64 without improvement.
I've upped Brute Force to 16 with little/no improvement.

Testing continues.....

[Morne]

i've had good results with IRMap and ticking ON "Detail enhancement" and also very important "Check sample visibility" (this will clean the "leaks" or "dirty" effect it's making)

Also if you have a VRayLightMtl applied to it, try playing with the "Direct Ilumination" ON and try OFF (sometimes the one gives better and faster results than the other)