shadingerrors

A public forum for discussing and asking questions about the demo version of Octane Render.
Forum rules
For new users: this forum is moderated. Your first post will appear only after it has been reviewed by a moderator, so it will not show up immediately.
This is necessary to avoid this forum being flooded by spam.
arail
Posts: 12
Joined: Tue Apr 06, 2010 1:34 am

I seem to get shading errors in Octane if I have smoothing on but I get faceting if I have it off.
Any suggestions concerning what I can do about that?
The shading errors are more pronounced if the model was exported to modo from another application than they are if the model originates in modo.
Freezing my geometry is a solution but at the expense of a much heavier model.

Sorry for the novice questions but I'm just starting to learn about rendering.

By the way - I LOVE the daylight in Octane.
Attachments
amboerrors.JPG
User avatar
Chris
Licensed Customer
Posts: 439
Joined: Thu Jan 14, 2010 5:01 pm
Location: Norway

Your mesh is to low poly. Insert a few edgeloops around the edges you have problems with and you should be fine.

Cheers.

Chris
________________________________________________________
Win 7 64 | 1x GeForce GTX Titan | AMD Phenom II X6 3.20Ghz | 16GB
User avatar
vagos21
Licensed Customer
Posts: 61
Joined: Wed Apr 07, 2010 4:51 pm

or, as said before in other threads, you can "detach" the polygons according to the smoothing groups in 3ds max by hand, or using a little handy script found here: http://www.scriptspot.com/3ds-max/scrip ... hard-edges
Good luck!
User avatar
radiance
Posts: 7633
Joined: Wed Oct 21, 2009 2:33 pm

you can just enable the use of smoothgroups in the obj import preferences in octane to have octane do this for you on import.

Radiance
Win 7 x64 & ubuntu | 2x GTX480 | Quad 2.66GHz | 8GB
rodney71
Licensed Customer
Posts: 43
Joined: Tue Mar 02, 2010 7:08 pm
Location: Canby, OR

I'm finding the same thing with objects generated in Modo (401) and saved or exported to OBJ. I have the import of smoothgroups turned on in the preferences. this image is just a simple cube and cylinder. enabling the smooth feature in material properties definitely helps smooth out facets but introduces these undesirable dark shaded areas.

Image
Rod
Asus P6T Deluxe V2
Intel core i7 920 (2.66 GHz quadcore)
12 gig RAM Kingston HyperX
BFG GTX 285 OCX
CPU cooling - Noctua NH-U12P SE2
OCZ Vertex Turbo 120 GB Sata II SSD
Windows 7 Ultimate 64bit
User avatar
Son Kim
Licensed Customer
Posts: 90
Joined: Fri Jan 22, 2010 5:02 pm
Contact:

rodney71 wrote:I'm finding the same thing with objects generated in Modo (401) and saved or exported to OBJ. I have the import of smoothgroups turned on in the preferences. this image is just a simple cube and cylinder. enabling the smooth feature in material properties definitely helps smooth out facets but introduces these undesirable dark shaded areas.

Image
interesting error :)
Last edited by Son Kim on Thu Apr 29, 2010 3:30 am, edited 1 time in total.
User avatar
greg.thoman
Licensed Customer
Posts: 132
Joined: Thu Apr 08, 2010 7:59 pm

I'm pretty sure that the smoothing toggle in Octane only smooths the normals, not the mesh, which gets rid of faceted edges. Octane, in this case, is trying to render a cube without edges and corners, which is why the cylinder is only shaded wrong at the top and bottom.
Somebody correct me if I'm wrong, or say it more clearly, I haven't been doing this too long.
AMD Phenom II X6 3.2 || 12 GB DDR3
GTX 480 1.5GB X 3 Liquid Cooled
RaidMax 1000W PSU || Corsair 850W PSU
MSI NF890-G65 Mainboard || Windows 7 64 Bit
arail
Posts: 12
Joined: Tue Apr 06, 2010 1:34 am

I get it at the bottom of simple shapes and at the point where the back of a cylinder rounds away out of view.
It can almost make the object look semi transparent.
I think Greg is correct, maybe somebody can give us a more technical explanation of the difference between mesh smoothing and normals smoothing so we could understand it a bit better.

That's the downside so far.
The upside is that the light in Octane is beautiful.
I've been experimenting with very simple shapes in monochrome colors, and they look much more subtle and clear in Octane than in any of the other add on renderers that I've tried so far.
User avatar
PhilBo
OctaneRender Team
Posts: 553
Joined: Wed Oct 21, 2009 2:36 pm
Location: Warren, Michigan USA

Here are two quick attempts that I made.

In Blender, I didn't do anything to the default cube, but I put it on it's own material so that I could control the "Smooth" parameter of the material independent of the cylinder. For the cylinder, I used smooth shading and then used an EdgeSplit modifier which breaks the cylinder surface into the two caps and the side (while still retaining a single object).
CubeCylinder1.png

I downloaded Modo and had a try in it. I couldn't find anything similar to an Edgesplit modifier, but Imported the scene into blender and performed the Edgesplit modifier on the cylinder and imported into Octane. I unchecked the "Smooth" parameter on the cube and left it on for the cylinder.
Modo-BlenderEdgeSplit.png
I just need to figure out how to do the similar function as Blender's Edge Split in Modo. But, since Blender is free, you could always just add it to your pipeline.

Phil
Win7 64| Two GTX 470s | Phenom II 920 | 8 GB
Win7 32| GTX 260 | Athlon X2 5000+ BE | 2 GB
User avatar
Son Kim
Licensed Customer
Posts: 90
Joined: Fri Jan 22, 2010 5:02 pm
Contact:

PhilBo wrote: I just need to figure out how to do the similar function as Blender's Edge Split in Modo. But, since Blender is free, you could always just add it to your pipeline.

Phil
Modo does in fact have an edge split, its under the Edge tab > Split. IMO it might be useful to have a edge split option for OBJ import, it can split base of boundary of materials, Thea does this - great time saver.
Post Reply

Return to “Demo Version Questions & Discussion”