Problem with SubD smoothing created from file

Next
 From:  tuananhnp
10841.1 
Hello, I'm doing some experiments with the built-in SubD conversion (from OBJ file) in MoI.
With a low-poly OBJ model imported, the SubD conversion creates very smooth surfaces.
However, it tends to convert medium-poly or high-poly OBJ into coarse, somehow faceted, surfaces.
The 1st screenshot shows two OBJ models. The 2nd screenshot shows their corresponding converted SubDs.

It maybe hard to see the difference by looking at the screenshot. But upon close inspection the roughness SubD surfaces are quite apparent.
I have attached the 3dm file below.

Is it a limitation of the built-in SubD conversion? Like it could only smooth simple polygon?

Image Attachments:
Size: 288.4 KB, Downloaded: 53 times, Dimensions: 1920x1036px
Size: 273.3 KB, Downloaded: 46 times, Dimensions: 1920x1037px
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  tuananhnp
10841.2 
I have tried both Patch Types under "SubD import options" with no luck.
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  tuananhnp
10841.3 
Here is the surface analysis comparison between 2 SubD versions.
Image Attachments:
Size: 560.4 KB, Downloaded: 31 times, Dimensions: 1723x982px
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
10841.4 In reply to 10841.1 
Hi tuananhnp,

re:
> It maybe hard to see the difference by looking at the screenshot. But upon close
> inspection the roughness SubD surfaces are quite apparent.

I think you're probably just seeing a display artifact in the real time viewport display where the display mesher is not making a lot of triangles in a few areas of your heavier model.

That's a normal type of display artifact and doesn't mean your actual model is rough. If you export out to a mesh format you can adjust the export mesh parameters and the "roughness" will be eliminated if you generate enough polygons.




re:
> Is it a limitation of the built-in SubD conversion? Like it could only smooth simple polygon?

No, it is just a mistake in your inspection method where you're closing examining the realtime viewport display mesh which is oriented around speed.

However, it is generally better with sub-d modeling to have as sparse of a control polygon cage as possible for several reasons - it's easier to control fewer cage points and data size will be less. When you have a high density control cage it becomes easier to have things like little bumps in the subd limit surface.

- Michael
Attachments:

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
 From:  tuananhnp
10841.5 
Oh my bad. I checked the way you did and it's indeed sooo smooth!
Thank you Michael for clarifying this. You're the man!
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged
 

Reply to All Reply to All