Reflection issue

[erva]

hi, when i use reflection for a plane, it produces some kind of shadow, which is not there when no reflection is applied. No overlapping geometry. It seems that the problem is consistent trough all the scene. I'm using max 2014, corona 1.2.1. System and display units are in cm.

[atelieryork]

Probably it's the ol' coronasun through refractive glass bug, that maybe will be fixed but not for a long while.

Try making your glass material Thin mode, or disabling Cast Shadows on the glass objects. Either should fix it.

[erva]

thank you, that did the trick. may you have a fortunate life friend :)

[atelieryork]

No problem.

[erva]

and another issue, that seems to be appeared with the new update:
when i use 1 - white for reflection and lower the glossiness to 0,3 and lower ( it starts to show sooner) - the reflection turns white. I didn't have such issue with previous version

[atelieryork]

This looks ok to me? Your ref colour is white, so that's what it's going to show. What are you expecting it to look like?

[erva]

i was expecting smthing like this - a similar material from a different scene

as you may notice, the first material has a white glow, wheres the second one doesn't. what is weird, that scene units, gamma and so on appear to be the same in both scenes.

[atelieryork]

Turn the chequerboard on/off. Maybe they'll match.

[erva]

thought so too, but no, doesn't change anything.
i just noticed in the old scene - which was created using an older version of corona - that the materials that where created earlier behave like the second material ( don't have a white glow). But as i try to create a new material with the exact same settings, it apears to be glowing white.

[romullus]

This is normal behaviour. Materials from older build has legacy checkbox enabled, so they use old incorrect GGX BRDF shader. If you uncheck legacy option or create fresh material, new more correct GGX is used. White glowing borders are expected. Reduce reflectivity to more believable values like 0.2-0.6 and your material should start looking better.

[erva]

i'm sorry, but where do i find this legacy switch? thanks
under material advanced options - it is grayed out

[romullus]

You can't enable legacy mode on new materials. If for some reason you need material with legacy on, you have to take any material from old scene and it will have that option.

[Bormax]

Hi
Pretty long time ago I found hidden BSDF switcher in Additional Params rollout of material (see the attachment). Now, when legacy mode is not active and I have to get rid off white edges from objects with low values of glossiness of material I use this switcher. I don't know is it a correct way or not, but it works for me. Another way is to use Falloff map in Glossiness map slot - it will make reflections on edges more glossy and the white edges will be gone too.
In attached examples all materials are the same, the only difference in first example is BSDF switcher's parameter, in second one the Falloff map is the only difference

[Juraj]

Reduce reflectivity to more believable values like 0.2-0.6

Are you sure ? All the other GGX models employed I've seen don't exhibit this to such an extent. I know at the moment the 0.0 in Corona =/= 0.0 (1.0 roughness) of original GGX but still, by this roughness other models showcase more diffuse. The Velvet/Glow effect is only apparent in Vray when specifically going for wide gamma in GTR attribute while at low glossiness.

One shouldn't need to adjust reflectivity at all. But Corona stays seemingly too reflective when you keep lowering glossiness, almost shining on occasions.

[romullus]

Reduce reflectivity to more believable values like 0.2-0.6

Are you sure ? All the other GGX models employed I've seen don't exhibit this to such an extent. I know at the moment the 0.0 in Corona =/= 0.0 (1.0 roughness) of original GGX but still, by this roughness other models showcase more diffuse. The Velvet/Glow effect is only apparent in Vray when specifically going for wide gamma in GTR attribute while at low glossiness.

One shouldn't need to adjust reflectivity at all. But Corona stays seemingly too reflective when you keep lowering glossiness, almost shining on occasions.

No, i'm not, i constantly change my workflow with materials since i met Corona. Sometimes i feel like i'm progressing, sometimes just stepping sideways. I think i never had that feeling that i'm 100% sure in what i'm doing with my materials :/

Before last GGX change i used to set reflections to about 0.8-0.9 and it worked pretty well, but after bug with dark edges of rough materials was fixed, problem with glowing edges appeared. I even reported it as a bug at first, but i was told that it is expected behaviour, so i adapted my workflow and started to use much lower reflectivity. Not sure if it's right or wrong, though. Maybe i should try fallof in glossiness like suggested in this topic, but i hate the fact that some additional map is needed for correction of existing BRDF. It feels wrong.

[Juraj]

No, i'm not, i constantly change my workflow with materials since i met Corona. Sometimes i feel like i'm progressing, sometimes just stepping sideways. I think i never had that feeling that i'm 100% sure in what i'm doing with my materials :/

Are you my twin :- ) ?

This is how I feel constantly.