Problemwith curved surface

Francesco Perusi

I have this problem I can't solve. Why the curve is like this and not perfectly round? I have the same problem with circles: they are not circles but like polygons.

Please help me because it ruins all the measures and I can't work!

Antonio Flores_21377

Hi Francesco,

Inside Studio if you don't choose intentionally to build polygonal geometries,
you are going to deal with Nurbs surfaces and curves an they are 100% smooth.

What you see on the screen is a visual approximation which you can tune
using the Visual Properties panel as shown at this link:

https://help.altair.com/studio/en_us/topics/studio/unity_basics/visual_properties_define_t.htm?hl=visual,properties

From here you can decide to increase the quality potentially slowing down the visualization speed
on complex models, or to reduce it maybe getting some extra speed when required.

It is a user choice.

Regards,
Antonio

Francesco Perusi

Antonio Flores_21377 said:

Hi Francesco,

Inside Studio if you don't choose intentionally to build polygonal geometries,
you are going to deal with Nurbs surfaces and curves an they are 100% smooth.

What you see on the screen is a visual approximation which you can tune
using the Visual Properties panel as shown at this link:

https://help.altair.com/studio/en_us/topics/studio/unity_basics/visual_properties_define_t.htm?hl=visual,properties

From here you can decide to increase the quality potentially slowing down the visualization speed
on complex models, or to reduce it maybe getting some extra speed when required.

It is a user choice.

Regards,
Antonio

The problem is that when i 3D print parts that i have built on inspire studio, i can see the edges on the curves and also if i extrude circles, the diameter on the object is slightly smaller due to the segments on the curve that makes the surface like a big polygon and not a perfect circle

Antonio Flores_21377

Hi Francesco,

If you are working with standard objects and tools which are made for creating Nurbs surfaces,
you can only experience visual approximation which you can verify if you use the Visual Properties panel
as I explained in last post.

If that happens and Visual Properties changes are affecting the visualization quality as it should,
this means you are dealing with Nurbs surfaces which is correct.

Now when you save the model for 3D printing you are saving it in STL or other polygonal formats
and while you do that the software has to make a conversion from Nurbs to polygons.

This conversion could be the source of the issue if you don't control it.
The best way to control the conversion is to converting the geometry BEFORE to export for printing.

The tool for doing this conversion is inside PolyNurbs tab and it is named "Nurbs to Poly":
https://help.altair.com/studio/en_us/topics/studio/polynurbs/nurbs_to_poly_t.htm

When I use it I normally activate:
1) Tolerance on Surfaces and I set mainly "Surface" which basically is a tolerance for the surface,
      and then sometimes I use also "Angular" if required and I set it in a range from 7 to 3
      based on my needs
2) Tolerance on Curves if AFTER tuning the above parameters I still see something wrong on edges
3) a few times I activate Face Dimension to prevent some edges from being too long

After you finished tuning the conversion from Nurbs to Polygon, then you can save in STL
or any other polygonal format so that when you open the file on the software of the printer
you will get no surprises.

Tuning the conversion parameters takes a bit of trial and error process but nothing so complicated.
This should cover the whole process.

Regards,
Antonio