CGAL evaluation: Three more features

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CGAL evaluation: Three more features

Riedel, Torge

Hi CGAL-list,

 

in addition to my already done evaluation of CGAL there was a request to check and test for three more features:

 

1. Offset

Given a mesh (open / closed surface) we want to create a new mesh by offsetting each triangle of the mesh in its normal direction by a given value and then combining all the new triangles to a new mesh by (re)fitting their sizes (and maybe adding / remove triangles). I searched CGAL online documentation, but without luck to find something.

 

2. Swept-Volume

Given a mesh (open / closed surface) we want to create a new (closed) mesh by moving the mesh along a given path (I think approximated by a polygon).

 

I have found CGAL::Polygon_mesh_processing::extrude_mesh, but it is limited (documentation) to open surface meshes. If it would supported closed meshes too, I could use the signature with a Vector_3 on each line of the polygon one after another.

 

3. Smoothing

Given a mesh (open surface) we want to create a new mesh by smoothing it. Starting with a simple example: Given a maximum angle between two triangles (the normals), sharp angles between two triangles will be smoothened by decreasing the angle while keeping the edge. Neighbour triangles will be modified too.

 

I have not found a promising method yet.

 

Hope my explanation was somewhat clear, but I can give more information or paint pictures. It would be great if someone can help to go further.

 

Thank you and best regards
Torge


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Re: CGAL evaluation: Three more features

andreas.fabri

Hello,

On 11/20/2018 5:03 PM, Riedel, Torge wrote:

Hi CGAL-list,

 

in addition to my already done evaluation of CGAL there was a request to check and test for three more features:

 

1. Offset

Given a mesh (open / closed surface) we want to create a new mesh by offsetting each triangle of the mesh in its normal direction by a given value and then combining all the new triangles to a new mesh by (re)fitting their sizes (and maybe adding / remove triangles). I searched CGAL online documentation, but without luck to find something.

offset computation is under development, although offsetting to the two sides and optimized for relatively small offsets.

 

2. Swept-Volume

Given a mesh (open / closed surface) we want to create a new (closed) mesh by moving the mesh along a given path (I think approximated by a polygon).

 

I have found CGAL::Polygon_mesh_processing::extrude_mesh, but it is limited (documentation) to open surface meshes. If it would supported closed meshes too, I could use the signature with a Vector_3 on each line of the polygon one after another.

A researcher working at Mainz and/or Braunschweig University had written a swept volume using the Surface_mesher.
No idea what the status is.

 

3. Smoothing

Given a mesh (open surface) we want to create a new mesh by smoothing it. Starting with a simple example: Given a maximum angle between two triangles (the normals), sharp angles between two triangles will be smoothened by decreasing the angle while keeping the edge. Neighbour triangles will be modified too.

Imagine you have a cube. Then your method will not work. No idea if it has a chance to work when the surface is relatively smooth.

Best,

Andreas

 

I have not found a promising method yet.

 

Hope my explanation was somewhat clear, but I can give more information or paint pictures. It would be great if someone can help to go further.

 

Thank you and best regards
Torge


CENIT AG, Industriestrasse 52-54, 70565 Stuttgart, Tel.: +49 711 7825-30, Fax: +49 711 7825-4000, Internet: www.cenit.com
Geschaeftsstellen (Branch Offices): Berlin, Frankfurt, Hamburg, Hannover, Muenchen, Oelsnitz, Ratingen, Saarbruecken
Vorstandsmitglieder (Members of the Board): Kurt Bengel  (CEO), Matthias Schmidt  (CFO)
Aufsichtsratsmitglieder (Supervisory Board Members): Prof. Dr. Oliver Riedel (Vorsitzender des Aufsichtsrats / Chairman of the Supervisory Board), Stephan Gier, Ricardo Malta
Bankverbindungen (Bank Accounts):
Deutsche Bank (BLZ 600 700 70) Kto. 1661 040 IBAN : DE85 6007 0070 0166 1040 00 SWIFT-CODE : DEUTDESS,
Commerzbank (BLZ 600 400 71) Kto. 532 015 500 IBAN : DE83 6004 0071 0532 0155 00 SWIFT-Code : COBADEFF600,
Registergericht (Registry court): Amtsgericht Stuttgart
Handelsregister (Commercial Register): HRB Nr. 19117
Umsatzsteuer (VAT) ID: DE 147 862 777
-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri