Strange Lines...

[mhagelsieb_cg]

Hello everyone...I've got some strange lines showing up in my test renderings. I'm guessing all of you could save me a lot of time and perhaps point me in the right direction.


As you can see, black lines are showing up on my walls. I've checked the modeling and everything appears to ok (no intersecting walls or planes, etc.) At first I thought it might be due to a large plane that was being rendered...but even after adding some lines to break up the plane it still showed up.

I'm guessing it's a setting I need to adjust. Thanks in advance! ;D

Update:

Thanks for all the comments! I really look forward to feedback whenever I post.

Well...I tried what dalomar suggested with no luck. I played around with it and the lines just wouldn't go away. At this point I'm pretty sure it has something to do with the sketchup file. I saved the settings and tried it on another model and everything looked ok [My other test is below]. The odd thing is that my sketchup model appears to be modeled correctly. Well, I'll send you the file dalomar and see what you think. Perhaps it has something to do with coming from a dwg file like Tom said. Who knows...


As to my workflow:
I start almost everything in Autocad and go from there. I typically only use my cad file as a reference and draw right over it. After that, I'm an old school sketchup user. I just start to model away. To tell you the truth...I prefer working on models rather than construction documents.

As for my settings:
I used a hdri for my environment. I've had a tough time finding one that I liked until I came across this one. Like fluke said, it's got kinda of an early morning feel.

Thanks again for the comments! ;D

[nomeradona_cg]

Re: Strange Lines...

wow. i havent seen like this before. they seem to be wireframe ah.

[dalomar_cg]

Re: Strange Lines...

It looks like they are mesh artifacts, and to be honest I have never seen anything like that before. Here's what I would suggest. The first is to change the Secondary ray bias which is in Global Switches at the bottom left corner. Change that to .01 and see what happens. The second thing is to switch Image Samplers to Adaptive Subdivision and disable any filters that you may have. Sometimes AA filters can cause artifacts, and although I've never seen it do that it is certainly a possibility. The third thing is to use Irradiance Mapping instead of QMC for primary bounces. QMC is extremely accurate, and sometimes it can add artifacts that won't be apparent in IR. If none of those options work, then please send the scene to either Joe or myself ( joeb@asgvis.com and dalomar@asgvis.com respectively) or upload it to our ftp site. Whatever's going on it is definitely wierd and definitely shouldn't be happening.

[fluke73]

Re: Strange Lines...

It defenitly looks like Wireframe showing up. But besideds that, i really like your light setup. Is this a shot directly from the render? How did you the background? I like the morning light kinda feeling in this image. Could you share this setup with us (when the wireproblem is solved)?

[TOM_cg]

Re: Strange Lines...

mmh, Could you share your workflow, please ?
Is that modeled is SU or imported from 3Dmax, ALLPLAN, archicad, ...
Seems that it is DXF triangulation artifacts.
But I can't figure out why they are showing up in your render.

Also, if this is native SU modeling, ( what it seems to be) did you do it from DWG imported into SU ?
I had those artefacts as well, in my walls, when I did them from DWG lines.
Please, share your model or a part of it. Or send it to me directly ? I'll see if I can analyse it

Cheers
TOM

[mhagelsieb_cg]

Re: Strange Lines...

Perhaps I should have just replied instead of modifying my first post.

Live and learn... ;D

[TOM_cg]

Re: Strange Lines...

As to my workflow:
I start almost everything in Autocad and go from there. I typically only use my cad file as a reference and draw right over it. After that, I'm an old school sketchup user. I just start to model away. To tell you the truth...I prefer working on models rather than construction documents.

Hello,
Don't look further, here is the flaw.
I had same issue in SU : faces seem to be coplanar, but can't close them, wierd dashed triangle,...
All come from the CAD reference, especially AutoCAD. I think it is due to the precision of CAD files and the one SU uses. Now I'm working from hi res JPG ( CAD drawings exported as JPG) them imported in SU then I draw the 3D on it. No more issue and it is as fast as the DWG method.
Cheers

[mhagelsieb_cg]

Re: Strange Lines...

Thanks for the reply Tom.

I'm curious to see if that is in fact the problem. The strange thing is that I've been working with Autocad files for quite some time now. Most of the time I only use them as a reference but there have been many occasions where I've used the cad work in my SU file. In any case, I'm wondering if changing the precision in autocad will correct my problems.

How do you go about exporting to jpg from Autocad? The only option I see is bmp. In regards to working with the jpg...Do you just eyeball where to draw your model? It seems liked it be easier to use the linework straight from cad (snapping to endpoints, midpoints, etc.).

Thanks Again! ;D

[joe_b]

Re: Strange Lines...

Co-planar faces are definitely a problem in Ray-tracing. Basically the ray-tracer can't determine which piece of geometry it is hitting in a non-arbitrary way if two things occupy the same space. Hence you get weird artifacts because sometimes it will act like it is hitting geometry A and other times it will act like it is hitting geometry B.