ragged lines where object meets ground

Started by Dune, May 09, 2016, 06:44:04 am

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Dune

Did anyone encounter this? I did a little test with double walled and single walled boxes, and found a difference. Any way to overcome this with existing single walled buildings?

Kadri

May 09, 2016, 09:21:12 am #1 Last Edit: May 09, 2016, 09:23:17 am by Kadri

The files in the RAR were not enough for me to see the problem Ulco.
There is just a TGO file without texture. The scene problem might be related to light, camera angle and texture etc.
Sorry not much a help. A basic gathered file might be much better. It rendered OK in my test.

But the object itself doesn't look like it does have a problem.
Have you tried just to translate the object a little in the Y axis?
Maybe a GISD problem?

Dune

Thanks, Kadri. I'll have another look, as another file went well. In my test I had the sun at 90º, and GI was set at 3 for some internal light, and gave me these results. Maybe that sun angle was the problem indeed. Hard to light a dark barn inside. I also tried to lighten an interior from a fire, but when you set the lightsource very bright, the walls get enough light, but the floor very near the source is much too light. If any of you guys have a good solution for that, I'd be much obliged.

j meyer

As for the lighting did you play with max distance?

Dune

No, I kept it as is, but I will play again and see what differences can be made. Thanks Jochen.

AP

What about using a Simple shape shader in the shape of a light fall-off using it as a position and mask for a Luminosity shader?

KlausK

May 09, 2016, 09:15:24 pm #6 Last Edit: May 09, 2016, 09:18:35 pm by KlausK
Dune, I am sure you`ve got something figured out by now.
Anyways, here is what I noticed: I had my camera set up in the middle room.
Since it has no floor with normals pointing inward the light somehow bleeds through
the edge of the polygon. The higher the AA the less that happens. But rendering time
is increasing of course. Obviously, not a good solution.
Here is what I did:
I masked off the planet with a simple shader which covers an area a little big larger
than the box, so that the planets surface is black. Then I put a plane into this room
which is exactely the size of the room. That is my new groundfloor, textured and
displaced and so on. No more bleeding through at the bottom of the box.
On the other hand if a doublesided box works I would do it this way in the modelling
phase anyway. The thickness in the doorframe and the window in the roof looks
much better this way in my opinion.

In the pictures I uploaded I used a spotlight inside the room to lighten up the walls and
the ceiling. It is closely placed beneath the ceiling, pointing down. Outer Radius of the
light cone set to 179.9 and the inner radius to about 40 or 50 to have a nice smooth transition.
Then it is just a question of fiddling with all the settings of the spotlight to find something
which works. Strength, Max Distance, Falloff Power, the cone angles and the Penumbra Gamma.
GI is set to default settings. After the spotlight is adjusted to a nice overall lighting I used the
strength on surfaces parameter in the Enviro light to brighten up the room as needed.
But that takes away some contrast.
Maybe this is useful somehow.

cheers, Klaus (sorry, for the lenghty post)




/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate

KlausK

I exported the gathered project if anyone is interested.
Please be careful with the textures in there. I forgot where they came from.
Way back magazine cdrom, I presume but I am not sure. Better not use
them in commercial projects, perhaps.

cheers, KlausK
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate

Dune

Thanks AP and Klaus. I think AP's solution wouldn't work here as it's a really 3 dimensional interior. I can imagine it to work over say a flatter area of interest. The spotlight is a good idea (why didn't I think of it?), and the extra floor also. I will try that. Perhaps it's logical for the single walls to bleed through, as the normals are pointing out. It's in fact a building made for exterior viewing. But I always thought that checking 'double-sided' would mean that a wall would be treated as if , well, double-sided. What I could do is duplicate the walls and reverse the normals, add it as an extra object (I am fed up with changing the original). They would be in exact the same location, hence not really thick, see if that would work.
Thanks again, guys.

AP

May 10, 2016, 03:52:46 am #9 Last Edit: May 10, 2016, 03:56:05 am by AP
No problem. It was a spur of the moment thought. Something like that could work for flat panel lighting, indirect lighting, tube lights and other more modern lighting themes.

KlausK

Doublesided in LW only means that you can texture both sides differently, if I am not mistaken.
I think that copying and pasting the walls, inverting normals and leaving them in the same position
won`t get rid of the problem, because both the polys still occupy the same space.
(Not that I have tried that, mind you). A little offset might help.
But in dynamic calculations like bullet or particles and cloth objects with thickness deliver better
and more reliable results. For lighting calculations which include ambient occlusion and GI this is
also true in most cases, as far as I know. Maybe next time you might model with thickness to begin with,
if that is not too much trouble. But for now the extra groundplane and the masking seemed to do the trick.
Whatever lighting power or glow I threw at the box it did not bleed thru anymore.
Curious, how you deal with it in the end.

cheers, Klaus


/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate

Dune

I'm afraid so, indeed, with the knowledge I now have. So I will model double sided in future if it's for interior shots. Matt explained to me what the problem is; the light of the microtriangles being calculated from their centerpoints; if these fall just outside the wall, light is being calculated from there (if I rephrase his wording correctly).
The medieval farm I will do luckily has a beam on ground level, which is fat enough. That should work.

bobbystahr

Quote from: Dune on May 09, 2016, 10:56:40 am
Thanks, Kadri. I'll have another look, as another file went well. In my test I had the sun at 90º, and GI was set at 3 for some internal light, and gave me these results. Maybe that sun angle was the problem indeed. Hard to light a dark barn inside. I also tried to lighten an interior from a fire, but when you set the lightsource very bright, the walls get enough light, but the floor very near the source is much too light. If any of you guys have a good solution for that, I'd be much obliged.


maybe try using a negative light at the same source as the fire light and playing with the falloff?
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Dune

Thanks Bobby. The spotlight at 180º works perfectly for lighting all, with an additional weaker lightsource for the fire itself.