Candide, check out the reflection of the cylindrical base at the bottom of the sphere.

I don't have access to the octane thread since I'm not a customer, but I definitely got the impression that Radiance had some walls up when presented with this issue in the earlier thread. I'm really disappointed to hear that they shut you out over there, Paq. You're one of the most respected members here and over in the modo forums, and I've never seen anything but helpful commentary from you.

->I can't have a discussion with Radiance myself anymore, looks I'm a bad little duck, never happy, and without any respect for the work done.

I don't believe that's true, your input and knowledge is most appreciated.

I don't know much about polygon stuff, I just know something doesn't work!

Marc

There's also a simple test file available here: CylinderOctaneTest.zip

That's a cylinder surface that is split into some slices. But the vertex normals on it come from the true cylinder NURBS surface, so creases or seams between the slices should not be apparent if those good normals are being used.

For example in Cinema4D importing the OBJ file from the zip file linked to above renders like this:



- Michael

Hi Michael

Just tried it both are faceted in Octane. For my understanding are the vertex normals in the .obj or in the .mtl file?

I hope this can be solved by the Octane crew. Thanks Michael for spending time on this as its not really your problem.

regards

Jamie

Hi Jamie, thanks for testing it.

> For my understanding are the vertex normals in
> the .obj or in the .mtl file?

They're in the .obj file - you can actually see them listed if you open the .obj file up in a text editor (try a text editor a bit more advanced than notepad, like notepad2 or notepad++), they're the "vn" entries that look like this:

vn 0.08659345 0.01440297 -0.99613961
vn 0.16999357 0.05883424 -0.98368731
vn 0.08664738 0.03098550 -0.99575706


When MoI exports an OBJ file, it puts the vertex normals from the smooth NURBS surface in there at the corners of each polygon that was created, so that when the polygon is rendered it can be shaded to closely resemble the original surface.

But if the stored vertex normals are not used and instead are just calculated by averaging the normals of adjacent polygon face normals together, it won't produce the same result.

- Michael

Hi Michael

The attached cylinder from blender works fine in octane. Any ideas why. I noticed that the vn entries in the blender file are shorter six figures after the decimal MoIs have eight. I have no idea if and why that would make a difference.

It does seem that MoIs files are different somehow. They will look at it in the next beta but if you have any ideas that would be great.

regard

Jamie

Michael's cylinder is designed to test that the vertex normals are superseding any shading groups / face normal averaging. The side of his cylinder is divided into 20 slices (polygon islands), each with their own shading group. If the vertex normals were being respected, it wouldn't look faceted between the slices. It works fine in Max, Maya, C4d, etc. Even in the opengl/directx viewports.

Hi Jamie - sorry maybe I wasn't clear with that cylinder test - the object in that previous cylinder test was not a "default cylinder" created by MoI, it was a test file set up similar to a model made up of multiple surfaces.

I made it by cutting a default cylinder into several different segments.

It's just an easy way to see what will happen on a more complex model made up of multiple surfaces that are joined together instead of just one big surface.


Probably your Blender one is just a default cylinder created in Blender? It most likely has not been cut up into different pieces, that's why there is a difference.


But there is also a pretty big difference between a polygon model that is created in a poly modeling program like Blender versus one that is generated from NURBS surfaces in a CAD program like MoI.


In a poly modeler you never actually have a "true" cylinder shape at all, it's all set up to work with polygons only and may use things like smoothing groups to separate polygons into different clusters that should have a kind of "fake smoothing" applied to them.


In a CAD program like MoI on the other hand, when you create a cylinder it is an actual cylinder spline surface. In a CAD program there isn't any "smoothing group" mechanism being used, things will look smooth if the actual NURBS surfaces are smooth, and creased if the NURBS surfaces are creased.

In that cylinder test file, the different NURBS surfaces are completely smooth to one another, so they are supposed to look smooth when rendered as well, despite them being in separate pieces. That's because the vertex normals in the file are supposed to be used for shading rather than just cooking up normals from the polygon faces.


> It does seem that MoIs files are different somehow.

It's not just MoI - it's stuff that is generated from any CAD program rather than a polygon modeling program.

CAD programs expect for a rendering program to use the vertex normals in the file to shade the objects, and not smoothing groups - smoothing groups should only be used for stuff coming from a poly modeling program and not a CAD program.


Note that in that same .zip file I also had an OBJ file saved from Rhino in addition to MoI - I thought you said that the Rhino file also showed the same segmented appearance problem in Octane as well?


EDIT: vodkamartini has described it more simply above as well.


- Michael

Hi Jamie,

> I noticed that the vn entries in the blender file are
> shorter six figures after the decimal MoIs have eight.
> I have no idea if and why that would make a difference.

No, that shouldn't make any perceptible difference.

The difference between those files has more to do with the way faces are organized with points shared between them.

The MoI example one is made up of several separate mesh pieces that physically touch each other but don't have "welded" points in common.

But they do have the same vertex normals where they are physically touching, that's why they should appear to be smooth with one another despite being in separate chunks.

If they don't appear to be smooth with one another, then it means that the stored vertex normals are not being used for the shading.

Every other renderer that reads vertex normals from the OBJ file will render that segmented cylinder as a totally smooth object without seams between the segments, but something seems to be different in how Octane is handling vertex normals that makes it appear different in Octane from other renderers.

- Michael

Hi Jamie, also one thing to note is that the default Blender OBJ importer also has a bug in it that discards the vertex normals instead of using them, so if you use Blender to test OBJ files with it could be easy to get a mistaken impression of what they are actually supposed to look like.

I have an updated version of the Blender OBJ import script which does not throw out the vertex normals here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3164.11

Maybe this is a source of some confusion, if imports into Blender were being used as some kind of model of how things are supposed to work...

- Michael

Hello,

Any chance of getting that Octane Render material test scene? Thanks.

I cannot speak to the official road map of Octane Render,as I have no control of that aspect of the Octane Render product, but from personal experience, I can confirm that the situation is not resolved 100% that the smooth group options do not rectify the situation.

I have tremendous respect for Radiance for his vision and skill to bring Octane Render to market. That is one of the reasons that I became involved with the project. I also love rendering in Octane as it allows me to "see" more than I could with other render engines.

I am for the most part, able to export items from MOI and make beautiful renders in Octane. It works great for my purposes. I can export a cylinder created in Moi using the standard tools and it looks perfect in Octane Render.

I tried the cylinder that you provided, Michael, in Modo and Blender using the script you provide. Using the OBJ import script, it is faceted in Blender and smooth in Modo. So, obviously, the code in Blender is not importing it correctly either, even with the modified script. Obviously, Modo was fine as many have stated. I also tried exporting this Cylinder as an LWO and using the MOI with Normals lwo import script listed on the MOI3D Resources web page, and it too creates a faceted cylinder upon import. So, I understand that you created the cylinder to prove a point and we'll try to use it as a test case to get the normals correct when the time is right.

I completely understand that many people may want to jump on SimLab or other comparable render engine if they feel that Octane is not the perfect companion to MOI3D now. It is something that I would like to have researched and improved in Octane, but cannot state that it will in fact be resolved for the 1.0 release.

We will continue to supply demos for users to evaluate prior to purchase, so please feel free to check it out before any purchase is made to ensure that Octane Render meets expectations.

Thanks for your patience with this issue. I will report back as progress is made.

Sincerely:

Phil Beauchamp
Refractive Software

Hi vodkamartini,

thanks for your kinds words ... I sometimes have my bad days too in fact ;)

Hi candide,

Well I don't have the original scene, I think Sam from the Octane forum made it. Anyway, it doesn't look right for that amount of polys.
I'll see if I can get it to make some comparaison.

Hi Michael, I've copy your message about the cylindre on the Octane forum, and also Jamie resume. Thanks for clear it up in a nice english.
Marc has posted the result in images, ... we will see how it turns.

Radiance is still speaking about smooth groups grgrgrrmmmpffffff ...

I'm not an Octane user (sadly, as I don't have a suitable card) but the vertex normals thing is something that seems to affect a great many of the 3D apps out there.

I am creating a ship model for a customer and the original brief required a pretty tight poly count. In order to achieve the count I exported individual obj's from MoI with a view to texture mapping in a poly modeller, merging the parts and exporting again as one obj. You would not believe the number of apps which cant handle this and create ugly faceted smoothing. Almost *all* of the UV & modelling apps I tried ignore the vertex normals in the file and seem to apply their own (incorrect) smoothing. So I feel your pain. This situation has been traumatic and has cost me a ton of time to find a workaround and is no fault of MoI's.

I can count on one hand the apps which worked for me...

1. UVMapper Pro
2. Milkshape
3. 3dsMax Trial (which of course, I can't use commercially)
4. Modified Blender script by Michael (which has issues instead with materials being mis-assigned)
5. Simlab trial
6. Probably 3D Paint Brush (trial expired)

Milkshape has a frustrating 65k poly limit but produces a nicely shaded model... for $35.

Why I wonder, are so many of these otherwise excellent tools crippled in this way?

Mark

(Looking at the above, I seem to have 6 fingers on one hand!)

Hi Phil, just some additional info on this one part:

you wrote:
> I also tried exporting this Cylinder as an LWO and using the MOI
> with Normals lwo import script listed on the MOI3D Resources web
> page, and it too creates a faceted cylinder upon import.

Actually what happens there is the normals are loaded (as long as you had welding turned off), and are actually used in the 3D realtime view in Blender which will have a non-faceted cylinder in it - don't get confused with Gouraud shading artifacts which are a different realtime rendering thing.

But if you then try to render it with Blender's default render engine, the renderer apparently decides to ignore the vertex normals that are present in the model and instead calculates new ones (which will be greatly degraded for CAD data) just for the rendering.

I actually didn't realize there was this bad problem with the Blender render engine until just now. I don't know why it does that, it is really annoying. Please don't use it as a model of how vertex normals should be handled, it's really very messed up.

Here for example I've found a post of someone mentioning this same problem:
http://geheim.blender.org/forum/viewtopic.php?t=13141&view=next&sid=41ba63d8dcc1ad464905c435d109c552

If you use a different render engine in Blender than the default one, or probably if you export your model, those good normals can probably get used. Anthony who wrote that LWO importer was using the Sunflow renderer, which ended up using the good normals, here is his original post about it:
http://moi3d.com/forum/index.php?webtag=MOI&msg=979.1

- Michael

Hi all

Just to say:
obj files from MoI to (direct import) Thea Render = perfect result.

From Rhino to Octane by Osiris

Hi Pilou, those look cool! But if you examine it closely I think you can see some of the artifacts being discussed.

For example here it looks like a visible seam appearing in the shading:



And here it looks like a sudden jagged bounce in the reflection:




Those are the kinds of imperfections that would actually be gone if vertex normals were being handled properly. It kind of gives an appearance of bumps or creases in those areas when probably the actual NURBS model was actually silky smooth there.


It's really sad to have such great quality for many of the other aspects of the rendering, but have problems in what is actually a really basic area.

- Michael

sure :)

Here is another really simple test - this one just has 1 single polygon in it so I don't think it can get any more simple than this.

I made a curved surface that looked like this:



But then meshed it with a really coarse angle setting to make just one polygon from it. But the vertex normals on the corners of that polygon will still be angled off to the sides (along the NURBS surface normals there) to give it the same kind of shading as the curved surface instead of it looking like a flat plane, here is what the mesh looks like when saving out from MoI:



Here is what it looks like when loaded into Cinema4D - note that even though it is a single flat polygon it has a kind of curved shading to it due to the vertex normals pointing off at angles:




The file is attached here as SingleCurvedPolygon.obj , can someone please load that into Octane and post what a rendering of it looks like? Does it look like a totally flat plane or does it have a gradient on it that looks similar to the original curved surface?

- Michael