geometry/indirect lighting issues - problem solved ;-)

[cocolas]

hello all,
this problem has shown up before, but to my knowledge there has never been a clear/definitive solution to it.........

sometimes, when a model/object is in indirect lighting, odd black shading comes up on the geometry where the mesh is divided up........an old suggestion was to check/uncheck "Smooth surface shadows" in the lights w/ vray shadows enabled.....but either checking it or unchecking it doesn't do anything....

see below:

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...ctLighting.jpg

I tried to add smooth modifier and also a subdivide to add polys to the mesh.....

w/ subdivide:

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...-wireWsubd.jpg

w/out subdivide:

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...lobby-wire.jpg

...and nothing happens.....

here's my settings...they are faily low/medium...but even at higher settings the problem persists...

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...aySettings.jpg

any help would be greatly appreciated

paul.

PS: the geometry having the problem was generated through a 2d spline, then simply extruded. Some of the objects have been booleaned as well....don't know if this matters..

[xaver]

dit you try uvw-mapping?

[cocolas]

yeah, those pieces all have UVW mapping on them as well....

paul.

[natty]

have you tryed upping your face/level coef..... that might help.

[cocolas]

Ididn't know about that...I always keep it really low...like 0.1 reduced from the default of 2......
someone said it renders faster....

I'll try that.....and see.

thanks Natty,

paul.

PS: the odd thing is that when I turn my skylight off/not use it.....all surfaces come out perfectly smooth...even though dark, because of the lack of light....

[cocolas]

I tried bumping the 'face/level coef" to 2.5 and set a high Imap settings....the problem is reduced but still noticable......especially on the side of the stairs...

and the render times quadrupled from the above version

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...tLighting1.jpg

can't quite point to what it is....


paul.

[J_Bug]

Hi Paul,
I think I recall having a similar problem with AA set to 1. Have you tried rendering with Adaptive AA?

--Jon

[cocolas]

Hi Jon,

I've tried that and unfortunatly it doesn't seem to do much......
probably the most effective thing I found is to apply an optimize modifier to the affected geometry.....that reduces the segments/faces w/in the mesh adn therefore reduces this effect...but it's certainly not a solution...since some meshes optimize better then others.....

here's a new one w/ optimize applied to the pieces that have the problem....plus high Adaptive AA (1/3) (I also tried simple two-level 2/4) .....
as you can see the problem persists on the side of the stairs...based on the optimized mesh....

ftp://ftp.hdrinc.com/4OMA/4cocolas/v...tLighting2.jpg

paul.

[ventil185]

Hi, i usually got that problem, and it works for me if in the editable mesh,
select by polygon and select all polygons manually where that happen,
and in the Surface Properties click in Auto Smooth.

Hope that helps.

[DaForce]

On your main lights, do you have smooth surface shadows ticked?

hmm just re-read the spots....what i said is probably irrelevant....worth a shot tho.

[cocolas]

@DaForce: thanks, but I tried to check and uncheck "smooth surface shadows" for the lights and didn't change anything......

@ventil185: I haven't tried that yet..but I'll give it a shot...thanks for the suggestion. I sent the file to vlado as well......we'll see what happens...


paul.

[DaForce]

try these 2 things.

1. Select all objects in the scene and apply a plain gray vray to all objects and render. result?

2. Select all objects and apply a tesselate modifier to everything, and render. results?

then try a combination of the 2.

I have a feeling that No.1 will result in a clean render.

see how you go.

[cocolas]

@ DAForce:
I tried both your suggestions...but nothing...

@ventil185:
I tried that...selected the problem geometry by polygon and apply auto smooth in the surface propreties......and didn't seem to work...


thanks anyway...........we'll see if vlado has something to say about it....or I might have to redraw the peices again...


paul.

[cocolas]

hey all,

just wanted to update you al on this problem in case someone has run into it or might run into it in the future....
after sending my file to vlado he found a solution that worked out....and smoothed the edge shadows that the above renderings were having...here's he's solution:

"Uncheck the option "Check sample visibility" in the Advanced
irradiance map parameters and it will be fine. It turns out that it
doesn't work very well for convex shapes with low polygon count."

anyway, the above works for me and hopefully for those of you that have/had this problem

paul