0026935: Implement Thicken Sheet in OCCT

Notes
(0048648) msv (developer) 2015-11-30 12:32	In order to implement such feature it is needed first to specify how it will be done. OK, we have functionality that makes offset shell of a shell. But in order to make solid we need to define how to construct the surfaces between original faces and their offsets. Without well-defined specification the development of a new feature is not possible.

(0050383) alainb (reporter) 2016-02-03 16:18 edited on: 2016-02-03 16:20	I very much agree with original poster that "Other modeling engines, such as ACIS and Parasolid, have the functions to thicken a sheet with a specified thickness. It's very useful feature to construct solids from sheet.". It is a feature that is missing from OCC. You may be interested in this thread : http://forum.freecadweb.org/viewtopic.php?f=9&t=3248 [^] As for the specification although not expressely stated by original poster, I think that most users would resquest that thickening be done normal to the surface at any point.

(0050656) Vico Liang (developer) 2016-02-12 05:43	Dear msv, Yes, I agree that it need well-defined specification to construct the surface between original faces and their offsets. I suppose the surface can be ruled-surface to connect the original faces and their offsets. Does OCCT have schedule to implement such feature? I'm sure this modeling feature will be a big hilight of OCCT.

(0050657) Vico Liang (developer) 2016-02-12 05:51	Salome stated that it implements its own offset feature in latest release base on OCCT6.9.1. Why not consider to make it in OCCT?

(0050842) msv (developer) 2016-02-16 18:31	I consulted with SALOME experts, and this is the answer: In fact, SALOME does not implement any specific algorithm of thickening, it just uses OCCT functionality, namely: • Create thick solid from face or shell: FACE or SHELL -> SOLID BRepOffset_MakeOffset myOffsetShape(aShapeBase, anOffset, aTol, BRepOffset_Skin, Standard_False, Standard_False, GeomAbs_Intersection, Standard_True); • Create hollowed solid (by pointing faces on which material is removed): SOLID -> SOLID BRepOffsetAPI_MakeThickSolid aMkSolid(aShapeBase, aFacesToRm, anOffset, aTol, BRepOffset_Skin, Standard_False, Standard_False, GeomAbs_Intersection); I am sorry that I was unaware of such feature (it is impossible to know everything by one person :) ). Indeed, this is available by the Draw command thickshell: Draw[16]> help thickshell thickshell : thickshell r shape offset [jointype [tol] ] I have attached the snapshots of original shell and result thick solid: thickshell res shell 0.2 i

(0051494) Vico Liang (developer) 2016-03-10 04:49	Dear msv, Sorry for later responsing. I checked the class BRepOffset_MakeOffset. It implemented the thicken feature as your described. But there is no entry in public API to use this feature(BRepOffset_MakeOffset is not a public entrance i think). So why not make the thickness parameter avalible in class BRepOffsetAPI_MakeThickSolid? OCCT have such wonderful feature, why not let outside world know?

(0051598) msv (developer) 2016-03-14 15:17	Dear Vico, Though BRepOffset_MakeOffset is not present in User Guide it is still a public API. It presents in the reference manual (http://www.opencascade.com/doc/occt-6.9.1/refman/html/class_b_rep_offset___make_offset.html [^]). Of course, it would be nice to make an entry for this functionality in BRepOffsetAPI_MakeThickSolid, and properly update documentation. If you have time and willing to make such contribution you are very welcome.

(0051608) Vico Liang (developer) 2016-03-15 06:32	Dear msv, Yes, BRepOffset_MakeOffset is accesible for public user. It would be better to make such change in OCCT internal team. The priority should be low.

Issue History
Date Modified	Username	Field	Change
2015-11-29 18:36	Vico Liang	New Issue
2015-11-29 18:36	Vico Liang	Assigned To	=> msv
2015-11-30 12:32	msv	Note Added: 0048648
2015-11-30 12:32	msv	Target Version	7.0.0 => Unscheduled
2016-02-03 16:18	alainb	Note Added: 0050383
2016-02-03 16:19	alainb	Note Edited: 0050383	View Revisions
2016-02-03 16:19	alainb	Note Edited: 0050383	View Revisions
2016-02-03 16:20	alainb	Note Edited: 0050383	View Revisions
2016-02-12 05:43	Vico Liang	Note Added: 0050656
2016-02-12 05:51	Vico Liang	Note Added: 0050657
2016-02-16 18:31	msv	Note Added: 0050842
2016-02-16 18:32	msv	File Added: shell.PNG
2016-02-16 18:32	msv	File Added: thicksolid.PNG
2016-02-16 18:32	msv	Assigned To	msv => Vico Liang
2016-02-16 18:32	msv	Status	new => feedback
2016-03-10 04:49	Vico Liang	Note Added: 0051494
2016-03-10 04:50	Vico Liang	Assigned To	Vico Liang => msv
2016-03-10 04:50	Vico Liang	Status	feedback => assigned
2016-03-14 15:17	msv	Note Added: 0051598
2016-03-14 15:17	msv	Assigned To	msv => Vico Liang
2016-03-14 15:17	msv	Status	assigned => feedback
2016-03-15 06:32	Vico Liang	Note Added: 0051608
2016-03-15 06:32	Vico Liang	Assigned To	Vico Liang => msv
2016-03-15 06:33	Vico Liang	Status	feedback => assigned
2016-03-15 09:33	msv	Priority	normal => low

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