Recent content by blobfish

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    How to differentiate between a circle and an arc

    The parameter range will describe a circle not necessarily (0, 2*PI) parameters. Something like this is legit. BRepBuilderAPI_MakeEdge em(gp_Circ(gp_Ax2(), 1.0), M_PI, 3.0 * M_PI); assert(em.IsDone()); TopoDS_Edge anEdge = em; assert(BRep_Tool::IsClosed(anEdge)); In addition with parameters...
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    Manifold Geometry blog and AAG

    @Quaoar I recently found your blog and finally took the time to read it all. Great info and thanks so much for putting it out there. One subject that grabbed my attention was the Attributed Adjacency Graph (AAG) as I have done quite a bit of similar work. Out of curiosity, I took a peek at the...
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    Sloppy Tolerances

    I see. Yes IGES is a mess. The only way I was able to fix iges was to untrim all faces and 're-trim' them to each other. That was difficult to work through using a GUI. I never tried to write code to automate it. I am a big believer in remodeling everything from scratch. Of course that is not...
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    Sloppy Tolerances

    Yeah the "tighten.SetTolerance(inShape, Precision::Confusion(), TopAbs_WIRE);" call sets all edge and vertex tolerances to Precision::Confusion. Then the "ShapeFix::SameParameter(inShape, false))" loosens the tolerances to acceptable values. That is the idea anyway. It appears to be working so...
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    Sloppy Tolerances

    Been looking into working around an offset bug. As the bug report describes, some offset routines just flat out assign 0.001 as a tolerance without any calculation. Upon investigation, it appears that most, if not all, the settng of tolerance values are predicated upon the new tolerance being...
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    NURBS libraries (excluding OCCT)

    verb nurbs
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    STEP features | How to communicate threads via a STEP file?

    IMHO: This is another little dirty secret of cad vendors. They claim they support step and the ignorant will see the imported step geometry on the screen and say "yup we got it". But like most things, the devil is in the details. They choose not to support the extra step data because, they want...
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    Geometric constraint solver

    Yes they are complicated. I chose to use solvespaces library and have been happy with the results. If GPLV3 is acceptable, I would recommend you check that out. I would be skeptical of occt solver, as occt released a software product where they used freecads solver. If I remember correctly.
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    Interfacing OpenCascade with NetGen

    I got the cadrays program working on my debian box, but the graphics of the entire application was FUBAR. That was probably just my system. I don't buy graphics cards and run the prop. drivers on them. I also tried to create a test program that used occt viewer with ray tracing, but like most...
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    Interfacing OpenCascade with NetGen

    I was contrasting our approaches. I am creating a plane on the bounding sphere with the size of the bounding sphere radius. On this plane I create a uniform grid of points to fire rays into the mesh. With that method, the 'vertical' walls of mesh are indeterminate. With your method, the vertical...
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    VTK vs AIS

    I agree 100%. A few years back OCC put out a message about wanting to hire opengl developers because they wanted to develop a new graphics API. I did a huge eyeroll. I understand their dilemma, they are trying to sustain a business so they have to go where they think the money is. Unfortunately...
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    Interfacing OpenCascade with NetGen

    yes undercut One of the things I wonder about, is the 2 vertical walls that are orthogonal to test direction. These 2 are accessible but no 'hits', so how to determine whether an orthogonal face is accessible? Maybe for those faces, your approach is used where the ray start on the face and...
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    Interfacing OpenCascade with NetGen

    I created a 'poor mans' ray tracer. 16,641 points in about 2 seconds.
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    VTK vs AIS

    I haven't used either so my opinion shouldn't count for much. IMHO: I have enough bugs from occt and I never use it for anything that I can do anywhere else. Isn't VTK made by the same people that came up with cmake? ${THAT_IS_ALL_I_NEED_TO_KNOW}. I have used coin3d and OpenSceneGraph(OSG). I...
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    Interfacing OpenCascade with NetGen

    Thanks for sharing this.
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