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Untitled1.csg (151 bytes) |
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Per guidelines, please open a forum thread first to let the community know. (post the link to the forum thread and post this ticket in the forum thread linking it back here) |
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Try the following changes 590 def process_rotate_extrude(obj, angle): 605 myrev.Angle = angle 614 angle = float(p[3]['angle']) |
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So rotate_extrude_action should look like def p_rotate_extrude_action(p): 612 'rotate_extrude_action : rotate_extrude LPAREN keywordargument_list RPA REN OBRACE block_list EBRACE' 613 if printverbose: print("Rotate Extrude") 614 angle = float(p[3]['angle']) 615 if (len(p[6]) > 1) : 616 part = fuse(p[6],"Rotate Extrude Union") 617 else : 618 part = p[6][0] 619 p[0] = [process_rotate_extrude(part, angle)] 620 if printverbose: print("End Rotate Extrude") And process_rotate_extrude Should look like def process_rotate_extrude(obj, angle): 591 newobj=doc.addObject("Part::FeaturePython",'RefineRotateExtrude') 592 RefineShape(newobj,obj) 593 if gui: 594 if FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/OpenSCA D").\ 595 GetBool('useViewProviderTree'): 596 from OpenSCADFeatures import ViewProviderTree 597 ViewProviderTree(newobj.ViewObject) 598 else: 599 newobj.ViewObject.Proxy = 0 600 obj.ViewObject.hide() 601 myrev = doc.addObject("Part::Revolution","RotateExtrude") 602 myrev.Source = newobj 603 myrev.Axis = (0.00,1.00,0.00) 604 myrev.Base = (0.00,0.00,0.00) 605 myrev.Angle = angle 606 myrev.Placement=FreeCAD.Placement(FreeCAD.Vector(),FreeCAD.Rotation(0,0 ,90)) 607 if gui: 608 newobj.ViewObject.hide() 609 return(myrev) |
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@chennes is this on your radar? |
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It is now :) -- I'll implement @keithsloan52's fix and add a unit test. |
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Update: that fix addresses the angle issue, but does not implement $fn, which will be a more complex fix. |
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$fn is optional, to quote the OpenSCAD documentation "$fn is optional and specifies the resolution of the linear_extrude (higher number brings more "smoothness", but more computation time is needed)." It is all about creating a smooth a mesh. Now if the user has the workbench option 'maximum number of faces for polygons set to a sensible value, then any OpenSCAD circle, polygon with greater than setting should be imported as a circle so $fn should not matter. |
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OpenSCAD users often use $fn to deliberately create non-smooth objects: in this particular bug report it seems that @laughingrice does indeed want a pyramid, and not half a cone. I am handling it the way we do in the cylinder code: if $fn is larger than the MAXFN value in the user's preferences we treat it as infinite, but if it's lower we treat it as though the user is deliberately creating a faceted surface. |
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Sorry don't follow, in that what is being extruded is on the stack, so should already be subject to the $fn for the operation that created it. Not sure that applying $fn to something that is already on the stack is a good idea. What is on the stack could have been created by a number of OpenSCAD operatives. |
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I've attached an image of what OpenSCAD generates for this operation. Example2.png (24,925 bytes) |
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So the issue is with a low value of $fn not a high value. |
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Right - I am following the example of the logic found in the cylinder code: |
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I seeSo the $fn is determining the base of object and what is on the stack the sides. Was not aware that was what it was doing. image.png (15,048 bytes) |
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Will teach me to read the manual rather than make assumptions, thought it was like extrude with an angle, rather than rotate about the z axis. Tried And get the result as per picture. The problem I see is that when the rotate_extrude gets to be executed, what is to be rotated round the z axis is on the stack. (Being on the stack is a result of CSG being a script type language that has to be parsed.) Now with a low $fn, the $fn needs to be applied to things on the stack i.e. retrospectively and what is on the stack could in general be quite complicated, there is no rule that says it has to be one simple shape. Image 14-03-2021 at 11.34.jpeg (39,634 bytes) |
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Forget what I am saying, the problem is not what on the stack it, it if a low $fn value is specified one has to use something other than a Part::Revolution to get the end result. Part::Revolution works when one want to make a smooth rotation. Have to code polygon once as per shape on stack and then at $fn * angle / 360 degrees with a cross section as per shape on the stack. |
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Another thing to watch for is there is a rotate_extrude_file see def p_rotate_extrude_file(p): 'rotate_extrude_file : rotate_extrude LPAREN keywordargument_list RPAREN SEMICOL' It currently calls process_rotate_extrude(obj) so would barf as the definition for process_rotate_extrude does not set angle as a default. I would have to check if passing a file also allowed an angle to be specified. |
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I've got the "prism" (for lack of a better term) code working fine and matching OpenSCAD if the shape being extruded does not contact the axis of rotation. I am using makeRuled() to connect the ribs that are created by revolving the original 2D shape. In the OP's bug report, though, that triangle has a line along the axis of rotation, so I can't use makeRuled() to create the surface we need. If you have any suggestions for how to connect the edges together I am all ears! I posted about it here: https://forum.freecadweb.org/viewtopic.php?f=3&t=56631 |
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GDML has a much richer set of Solid Graphics than FreeCAD, you might checkout out https://geant4-userdoc.web.cern.ch/UsersGuides/ForApplicationDeveloper/html/Detector/Geometry/geomSolids.html If you find anything that is similar or matches the bill. Look at GDMLObjects.py in repro https://github.com/KeithSloan/GDML Then look for the def createGeometry which draws the said Shape I am thinking on the lines of Polyhedra or makeFrustrum function. |
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PR: https://github.com/FreeCAD/FreeCAD/pull/4629 |
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https://github.com/FreeCAD/FreeCAD/commit/4e58747c16c5f05814d540f93fee16e128c1ed67 https://github.com/FreeCAD/FreeCAD/commit/dfd683d46451b2a2e00bf2f9a5efff814613764c |
- Anonymous
