Meanwhile, knowing about the issue, I started to edit my scenes, where the mirror tool was used. Adding xform+ normals modifier works fine, unfortunately it will affect all instances ie original geometry as the mirrored counterpart, making become the modifier as reference depending on the geometry might lead to crash if highpoly and high in count.TAO wrote: ↑Fri Mar 26, 2021 2:53 pmFliping the normal is exactly the case. That's the same for others rendered like Arnold and even viewport in case of visible reflection. they already add it in the knowing issue in Autodesk knowledge.B.Y.O.B. wrote: ↑Fri Mar 26, 2021 2:42 pm Mirroring probably makes all normals point in the other direction.
Some LuxCore materials act differently depending if it's a backface or frontface, e.g. glossy is only specular on the frontface, but behaves like matte on the backface (https://github.com/LuxCoreRender/LuxCore/issues/301).
You should probably check how other renderers in 3ds max handle this and follow their behaviour. Maybe they detect mirrored objects and flip their normals.
The issue will affect only the reflection, as it said on the Autodesk page.
Screenshot 2021-03-26 155146.jpg
The best and fastest way is simply to mirror by using "mirror tool" by selecting "reference", this will ad automatcally on the flipped objects and only on those, the xform+normal modifier. Instancing is mantained. I see that after doing so the mirrored geometry is black, turning off or deleting the normal modifier fix it. MaxtoLux renders like a charm.
for those interested, dealing with modifiers on large scenes I suggest to look for a free script "bga_deletemodifiers_v2.ms"
I think that autodesk won't work on the mirror tool code to update it, I see it's been long time this issue is reported and known,
The reference option is the work around.