Hi,

I'm using C4D and Maxwell and I often got shading issues even when setting the phong tag to smooth to 5° and not the default 80°

.OBJ or .3DS ? Quads + tris or tris only ? Export ngon ?

I sometimes set export options like:

Angle: 5°
Divide all bigger than 5cm (for small objects)
Avoid ratio bigger than 10
Avoid smaller than .2mm

Hi DesuDeus, definitely do _not_ use 3DS format if you have a choice - it's a very old format and has various limitations in it.

Generally for transfer to C4D you would want to use OBJ format, and Exporting N-gons should be fine. If you run into a problem with N-gons with any one particular model try doing "Export: Quads & Triangles" for that particular model.

> the phong tag to smooth to 5° and not the default 80°

When you use OBJ import, there should be a "normals" tag I think it's called which will should control how it is shaded totally in place of setting any phong angles like you're describing here. So when you do OBJ import make user the vertex normals are being loaded and that you're not either deleting the normals tag or have unset the option to import vertex normals. When the vertex normals come through those normals are from the original NURBS surface and will greatly help to make the shading look the same as the original NURBS surface.

One of the various limitation of 3DS format is that it does not have any way in it to store vertex normals, so you would need to mess with phong break angles and such if you're using that format and you'll usually get some various kinds of shading artifacts when the vertex normals are then created only by averaging polygon faces rather than having the original NURBS surface normals come through as you can get with OBJ import.

- Michael

And if you're exporting to Maxwell as a stand-alone program rather than inside of C4D, you would probably use OBJ format with "Export: Quads & Triangles" - some programs do not handle complex n-gons very well and can get confused with triangulating them. If you see things like triangles leaking outside of polygon boundaries that means the program is having difficulty processing n-gons and so in that case switch to outputting quads & triangles out from MoI so that you won't be giving that program complex n-gons to deal with. But C4D itself is pretty good at handling n-gons.

- Michael

Indeed I just export to OBJ with N-gons. It works great. No problems at all.


Peace,
Rich_Art. ;-)

Rich:
<<Indeed I just export to OBJ with N-gons. It works great. No problems at all.>>

..me too...
i think to have exported at least 200 models in C4D (R9-R10.5-R12) during last years,some of them very complex,just in one case i switched to"quad&triangles"
all exported successfully !

Here's an export to ngon
Imported with riptide pro
No phong tag in C4D
Render in maxwell

No smoothing at all

Here's another one
Quads + Tris

Hi DesuDeus, that does not really look like a geometry smoothing problem - is it possible that your object is particularly small or large and is running into some kind of distance related bias value in Maxwell?

Also your image looks pretty grainy in other spots, it could be possible that you just need to give it more time to crunch away to get better render quality on highlighted areas, the unbiased render mechanisms can be like that.

What does it look like if you use the built in C4D renderer instead of maxwell, does it look all proper there?

- Michael

Hi DesuDeus,

> Here's another one
> Quads + Tris

Looks like the same thing - probably not a problem with the geometry, more likely you need to give Maxwell more time to get more samples processed for the highlight areas.

Again, what does it look like if you use the regular plain C4D render rather than Maxwell, do you see problems in the built in C4D renderer or only when you use Maxwell in particular?

- Michael

Funny there are a lot of French faults words on the Riptide UI ;)

Here's in triangles
+ a render with no noise

My object is 29mm by 56mm by 146mm in MoI

It's scaled correctly in Cinema 4D (everything is scaled correctly, using an HDRI for light)

Here's another test without riptide pro

Hi DesuDeus, is the "no noise" one also done in Maxwell, or is it done in the C4D default renderer like I was asking about above?

Do you want to post the 3DM model file so that others could take a look at it and see if they can give you some tips about it?

Maybe Maxwell in particular is sensitive to something.

Do you have the normals tag in place when you are doing your renderer? Have you possibly done any kind of editing of the geometry that might invalidate the normals tag?

- Michael

The no noise version is maxwell yes

Here's the 3dm of the handle (in mm)
https://dl.dropbox.com/u/44982094/handle.3dm

The exported obj + mtl (triangles)
https://dl.dropbox.com/u/44982094/handle.obj
https://dl.dropbox.com/u/44982094/handle.mtl

It was build from two extrudes + fillets and the bigger part is a sweep + scaling rail + filets

Hi DesuDeus, I'm kind of losing track of what you're trying to show.


> Here's another test without riptide pro

Those seem to be looking good, is there a problem there?

Is it possible that your HDRI image is somewhat lower resolution and causing additional artifacts because of that?


It looks like you've got a screenshot there of the default C4D renderer which does not appear to have any kind of artifacts in it at all. If you're getting bad results specifically from Maxwell renders you will probably want to go to the Maxwell forum and see about getting some tips about what you can adjust in the Maxwell renderer to improve things, maybe you need to mess with some settings or use a higher resolution HDRI image or something along those lines.


- Michael

Does the "avoid smaller than X" can cause shading issues ?

The HDRI is high resolution and well made.

I will try to export my whole model again in ngon and use riptide pro with a phong angle of 5° + normals

Hi DesuDeus,

> Does the "avoid smaller than X" can cause shading issues ?

Well, it makes for rougher and coarser meshes being made on smaller sized pieces.

That setting is for making small sized details (ones smaller than the distance value that you put in there) to be done with a much rougher angle so things like little tiny fillets will use only a small number of polygons rather than little sized rounded pieces using the same number of polygons as regular sized polygons.

You should generally only use that setting if you are trying to optimize for a lower polygon count. If you're trying to get a high detail model don't set that at all (or set it to 0 to clear it), since it's all about reducing mesh density.

- Michael

Hi DesuDeus,

> The no noise version is maxwell yes

It looks like the "no noise" version does not have quite the same amount of problems that you are indicating in red arrows in the other attached image above, is that correct?

It seems to me that you probably have some different parameters in Maxwell that are not working well with your situation - if that's the case the solution is going to involve controlling those things in Maxwell, not anything to do with changing how the geometry is imported.

Again it looks like there are no artifacts on the render done with the built-in C4D renderer, is that correct? Or do you see any problems in that render too?

If you see no shading problems of any kind in the C4D built in render but you do see strange things in Maxwell, that tells me that Maxwell in particular does not like something about the model or environment or parameters that you are currently using, and if that is the case you will probably need to make some adjustments to make Maxwell more happy about the whole setup. You'll probably need to get some Maxwell-specific tips if that's the case.

Maybe some other C4D users will be able to test with your model to verify if they're able to get it over ok or if they see any problems too.

- Michael

No problems at all. Export with Ngons. Import with the native importer from C4D.






Peace,
Rich_Art. ;-)