Jagged appearance of clean surface

[shakedesign (Info)]

Hi all,

I have been experiencing some strange jagged appearance when constructing a 4-sided surface.

I have tried to modify the mesh settings, but it doesn’t improve.

However, in the surface analysis (env. map) it shows as a clean and smooth surface.

It just started happening recently. Anybody know’s what is going on?

[davidcockey]

The render mesh setting may be too coarse.
https://wiki.mcneel.com/rhino/meshfaq#
https://wiki.mcneel.com/rhino/meshfaqdetails

If changing the render mesh settings don’t fix the problem upload a .3dm file with the problem.

[shakedesign (Info)]

Hi David,
Thanks for your reply.
I have tried various mesh settings, as I already indicated. Thing is, I have been using Rhino for many years and this is happening more and more recently when creating surfaces, I found.
I’m working on Windows, but colleague of mine who is working on Mac experiences the exact same problem.

Please find the test-file below.

jagged_surface.3dm (148.8 KB)

[davidcockey]

Try moving the “Density” setting from 0.0 to 1.0. The render mesh with 0.0 is very coarse.

[JimCarruthers]

It seems to be a quirk or bug with that particular lighting mode, it’s ‘Arctic’ or something based off of it?

[Gijs (Gijs de Zwart)]

@JimCarruthers I think there is some self shading issues caused by the fact that the posted surface is a bit twisted, and with the original mesh setting this results in triangles with awkward aspect ratio.

@shakedesign In addition to the proposed change in density, set aspect ratio to something between 4 and 10, that should help with surfaces like these to avoid this issue.

[shakedesign (Info)]

Thanks you both for your reply.

Strange thing is that this never occured before ( have been using Rhino for almost 20 years) . And even in the shading (ground plane shadows) you can find the triangular artefacts.

.@Gijs Where do youset the aspect ratio to 4 -10? I can set the render mesh quality (simple) to 1.0 and then the artefacts also diasappear, but I guess that’s not what you mean…?

But as said, this never happend before.

[Gijs (Gijs de Zwart)]

Click on details in that window and you get more meshing options.
FYI: I opened your file in Rhino 6 and it showed the exact same issue with the same settings, so it could be that the mesh settings for default have changed. I will try to find if this is the case.

[shakedesign (Info)]

Usually I work with the following settings that give the overall best results:

I keep all parameters set to ‘0’, except the ‘Max distance, edge to surface’.
But now these setting give triangular artefacts as well for the ‘Smooth & Slower’ preset.

Surprising to hear that opening the file in RH6 also shows the same arftefacts…
Anyway, I gues I’ll have to play a bit more with these settings. Apparently the default settings have changed ‘behind the scenes’ like you mentioned.