Mesh to solid?

I've never done much with imported 3D objects.   We purchased a subscription to Automesher so we could import IGES and STEP files from customers into BricsCAD.    It works most of the time, but it creates "meshes".    I don't have any knowledge of "meshes".  And frankly, I don't really understand why you would create a mesh rather than a solid.   The Quad Tool doesn't play nice with meshes.  I've been unable to use the UCS face command, find centers, etc. when an object appears to made from thousand of "facets".     Is there a way to turn the mesh into a solid?

Comments

  • I presume no one ever responded to this thread because apparently, very few people use Automesher.   But we ended our subscription to Automesher over two years ago.    (We never had a single successful conversion with the program, and our requests for product support were ignored.)   When we dropped Automesher, we bought Communicator from Bricsys.  It works ok bringing in STEP files (most of the time), but I still have not been able to bring in a IGES file in a usable form.  The imports are not solids.  They are a collection of surfaces of zero thickness.  We can't snap to them, measure them, or make mods.   Has anyone here had any success importing IGES files into BricsCAD?  If so, how are you doing it?

    Attached is a model of a fan we converted from IGES.    You can see that this is not a solid model.  It is a collection of surfaces. 

    OD8025-24 SURFACES.dwg

  • Hi Jim,

    If your using BricsCAD V15 Pro or newer, then you will have access to DMSTITCH. This will convert regions and surfaces to solids if they are watertight. If it's not watertight then you will get a combined surface. DMSIMPLIFY is also available, which can be used to clean up solid geometry. In V16 there are some additional direct modeling tools. If you look in help under direct modeling commands you will find them.

    Attach your model converted to a solids. I placed them on separate layers to aid visualisation. Seems to have worked ok as far as I can tell.

    On import of IGES, this is available by using the communicator module. This also has settings you can adjust to stitch and simplify the model on import. That said there are a plethora of apps out there that convert IGES to dxf/dwg.

    Regards,
    Jason Bourhill

    OD8025-24 SOLID.dwg

    imageSolidModel.png
  • Jim Canale
    edited August 2019


    .....BricsCAD V15 Pro or newer, then you will have access to DMSTITCH. This will convert regions and surfaces to solids if they are watertight. If it's not watertight then you will get a combined surface. DMSIMPLIFY is also available, which can be used to clean up solid geometry. .......



    Jason,

    Thanks!  This has been a thorn in my side for a long time.  I did not know about DMSTITCH or DMSIMPLIFY.    I notice you broke the model down into pieces (frame, blade, and cowl), and put them on different layers.  Did you do that before applying DMSTITCH and DMSIMPLIFY?   Your fix appears to be useable, although I note there are some flaky areas where the three components do not mate well.     I will experiment with the commands.

    We have not installed V16 yet for several reasons... It is my understanding that most of the upgrades are to BIM functionality, which I never use.   And I have gotten the impression from reading postings, that V16 is still quite buggy, and a drain on system resources.  My computer is very slow, has only 3GB of RAM and runs a 32 bit OS.

    Jim
  • I notice you broke the model down into pieces (frame, blade, and cowl), and put them on different layers.  Did you do that before applying DMSTITCH and DMSIMPLIFY?   Your fix appears to be useable, although I note there are some flaky areas where the three components do not mate well.     I will experiment with the commands.


    I separated the model on to different layers after DMSTITCH for visualisation purposes to highlight the command had created multiple solids. The cowl does clash with the frame, but I think it could be fixed through a simple UNION. The clean-up steps would be dependant on what you are looking to achieve.

    Regards,
    Jason Bourhill



  • NOTE! For me at least. I had to convert the imported faces to REGIONS before BricsCAD would let me make solids.
    So work flow was. Import mesh - Explode mesh ( X - for explode) - change all faces to regions (REGION command) - convert to solid (DMSTITCH command)

  • Yes, that's how it works.
    I created an own palette with those 3 commands :)

  • @DFLY said:
    NOTE! For me at least. I had to convert the imported faces to REGIONS before BricsCAD would let me make solids.
    So work flow was. Import mesh - Explode mesh ( X - for explode) - change all faces to regions (REGION command) - convert to solid (DMSTITCH command)

    Thank you. I am going to try this sequence the very next time I work with meshes......

  • We have the latest version of BricsCAD installed now (V18.2.14). I've tried this procedure many times on imported meshes and find the usual result of the EXPLODE, REGION, DMSTITCH, and DMSIMPLIFY commands is often a solid with so many triangular facets, it is not usable. It's very hard to select the right snap because of all the facets.. 2D views can be generated, but they also have so many facets that circles and arcs can't be snapped to or measured. These meshes may be useful for other applications, but I don't understand how to use them with BricsCAD. Ideas anyone?

  • Well, my geometry consists mostly of simple Cubes in addition.
    There Stitching Workflow is tedious of course but at least I get
    useful and editable Solids.

    As long as these don't touch each other which makes conversion
    of all objects at once impossible or even impossible to select and
    separate Faces for a successful Stitching.

    Stitching is pretty useless of course if the source is an awkward
    complicated Mesh only, like a wash basin from a (mesh) library.
    Just converting such objects into Solids will not make them any
    more intelligent and I doubt even that it saves file size or accelerate
    viewport speed.

  • @Michael Mayer said:

    ...Just converting such objects into Solids will not make them any

    more intelligent and I doubt even that it saves file size or accelerate
    viewport speed.

    Mike,

    I just don't understand why BricsCAD provides tools to generate meshes. Why would you use them when you can use a solid?

  • Many CAD Apps have more or less basic Mesh support because
    Meshes exist in real world beside CAD.
    Even if these are not really what you want in a CAD it is better to
    have the option to bring them in and be able to do some
    basic editing.

    Without Support that would be no 3DS, Sketchup, ... import option,
    no STL printing output and such things.

    But you would not want to create new Meshes in your Solid Modeler
    CAD when you can use Solids.

    Also Meshes are part of DXF/DWG and Autocad has them,
    so Bricscad has them alone for ACAD compatibility

  • DFLY
    edited July 2018

    @Jim Canale said:
    We have the latest version of BricsCAD installed now (V18.2.14). I've tried this procedure many times on imported meshes and find the usual result of the EXPLODE, REGION, DMSTITCH, and DMSIMPLIFY commands is often a solid with so many triangular facets, it is not usable. It's very hard to select the right snap because of all the facets.. 2D views can be generated, but they also have so many facets that circles and arcs can't be snapped to or measured. These meshes may be useful for other applications, but I don't understand how to use them with

    BricsCAD. Ideas anyone?

    OK. There IS a way to get clean drawing if you absolutely must.

    I have posted it on a friends Youtube at (Sorry deleted link. Got some music copyright issues to fix. Hopefully I'll have it posted by tomorrow)

    A customer send me a crate lid mold igs file that I had to make drawings for. It got me thinking.

    The task is to make drawings, not to make solids (as much as I wanted them).

  • Meshes aren't very useful in CAD.
    There is no parametric or intelligence in Meshes.
    These are just defined by their vertices.

    In a 3D Polygon App there may be some parametric
    like circles or boxes but that is just in their Tools.
    Once converted into an editable mesh a circle will get
    a simple Polygon with n vertices that define Faces and
    their orientation.
    You can't even have holes in a face, it's more like you
    bend a face around that hole to get the supporting
    edges that "hold" that hole in place.
    A mesh volume is no real volume, just all faces pointing
    outwards will make that addition of connected faces
    looking like a volume.

    It is not easy to for a computer to detect if that is just a
    bunch of 3D polygons or should be a watertight volume
    that could also be represented as a Solid.
    And to determine if something may be meant as a circle,
    an algorithm would need to check the vertices positions
    and check if there may be a center point to which all vertices
    have the same distance. By applying a certain tolerance as
    mesh Apps aren't that precise.
    Or checking if a row of edges may be described as a curve
    or row of arcs, with certain tolerances for angles between
    edges, that may be meant as a hard edge instead.
    There would be needed an algorithm for all these many cases.
    Maybe done by the help of an AI.
    Something which is much easier for a human brain and may be
    faster by redrawing for CAD usage purposes.

    That is something worked on also for things like point clouds
    to convert these into more useful geometric objects.
    Basically the same problem with tolerances. E.g. what is just
    inaccuracy in a plastered wall and what what is already a
    stucco detail.
    So far point clouds are meant as sketch underlays to draw
    CAD geometry over.

  • @DFLY said:

    OK. There IS a way to get clean drawing if you absolutely must. I have posted it on a friends Youtube at (Sorry deleted link. Got some music copyright issues to fix. Hopefully I'll have it posted by tomorrow) A customer send me a crate lid mold igs file that I had to make drawings for. It got me thinking. The task is to make drawings, not to make solids (as much as I wanted them).>

    Thanks.. I will keep an eye out for the link.

  • @Michael Mayer said:

    Meshes aren't very useful in CAD. There is no parametric or intelligence in Meshes. These are just defined by their vertices........>

    Michael, I think I get your comments. Meshes are a totally different system for representing 3D objects.

    I usually try to find solid models of all the components I incorporate into my designs. Or I take the component, measure it, and make a 3D solid model from scratch. But still would be nice if someone would come up with a good conversion routine.

  • It was said that Bricscad is working on ways to improve stitching
    or auto stitching of things that import as loose faces.
    Those may also help in your case.

    Unfortunately most Library objects exist as Meshes even in the
    own libraries. Also often used is Google's Warehouse with Sketchup
    import. And lately noticed in Vectorworks, BIMObjects ™ are even
    Meshes deeply nested in Symbols (Blocks) extensively slow down
    VW's Viewports and Selection Highlighting.
    So you can keep these as they are as long as they don't cause larger
    issues but it is very common that important Library Objects, to be
    reused in the future or in many instances in a file get rebuild
    manually by Solids or other App specific Objects.

  • @DFLY said:

    @Jim Canale said:
    We have the latest version of BricsCAD installed now (V18.2.14). I've tried this procedure many times on imported meshes and find the usual result of the EXPLODE, REGION, DMSTITCH, and DMSIMPLIFY commands is often a solid with so many triangular facets, it is not usable. It's very hard to select the right snap because of all the facets.. 2D views can be generated, but they also have so many facets that circles and arcs can't be snapped to or measured. These meshes may be useful for other applications, but I don't understand how to use them with

    BricsCAD. Ideas anyone?

    OK. There IS a way to get clean drawing if you absolutely must.

    I have posted it on a friends Youtube at (Sorry deleted link. Got some music copyright issues to fix. Hopefully I'll have it posted by tomorrow)

    A customer send me a crate lid mold igs file that I had to make drawings for. It got me thinking.

    The task is to make drawings, not to make solids (as much as I wanted them).

    OK. Sorry I deleted my youtube link.

    It is now here: https://youtu.be/tIvRttwooKg

  • DFLY
    edited July 2018

    Hey BricsCAD developers, If you are there. There is a way to turn meshes back to solids.
    It is obviously more difficult than turning solids to meshes.

    The main problem is elliptical and spline solids.

    Basically rather than stitch planes to make a solid. CAD has to identify entities and replace them.

    Fortunately an elliptical solid leaves quite a distinct shape if viewed from all three planes. Of course it is quite processor intensive as CAD has to check the relationship of all points in a model from three angles and then identify if there are circles there. eg. 60 degree ellipse in the z axis and 30 deg ellipse in the y axis means you have possibly the head of a cylinder bent up 30 degrees on its x axis. Then Once CAD has all the ellipses identified it would have to see what they were connected to.

    Oval ellipses (eg angular slice through a cylinder) also could be identified by their points from x, y, and z views.

    Splines... sorry I don't know the maths of splines (I don't use splines in my solids, I don't even know if i can turn a spine into a solid).

    Bevels ? Bevels are always between two meeting surfaces. So deviation from the expected sharp edge should give CAD the information needed to recreate the bevel in solid form.

    I suppose the key word here is recreate. A solid is a mathematical entity governed by lengths and radii etc. Whereas a mesh is just points joined by lines and faces. (A bit like comparing vector graphics with raster graphics).

    Obviously there is a limit. Because some things are supposed to be meshes, like models of people and animals.

  • @DFLY said:
    Hey BricsCAD developers, If you are there. There is a way to turn meshes back to solids.
    It is obviously more difficult than turning solids to meshes........

    I viewed some of your video. Thanks. That's a lot of work to get some 2D views, and not what I want. I want a 3D solid model. I actually think it would be easier to buy the part, measure it, and make a 3D model from scratch, which is what I have been doing.

  • @Jim Canale said:

    @DFLY said:
    Hey BricsCAD developers, If you are there. There is a way to turn meshes back to solids.
    It is obviously more difficult than turning solids to meshes........

    I viewed some of your video. Thanks. That's a lot of work to get some 2D views, and not what I want. I want a 3D solid model. I actually think it would be easier to buy the part, measure it, and make a 3D model from scratch, which is what I have been doing.

    Yes. I would agree. If you want solids, you have to build them.

  • I second @Jim Canale about the options shown in the video are
    a solution or a tedious workaround.

    But the video was very interesting for me nevertheless, as it shows
    a lot of 2D workflows, which I don't often use or need and so am not
    very experienced in 2D and hope I can keep these in the back of my
    mind in case when needed.

  • @DFLY said:
    Hey BricsCAD developers, If you are there. There is a way to turn meshes back to solids.
    It is obviously more difficult than turning solids to meshes.

    ............
    Just viewed your video again, and realized I neglected to thank you for posting it. It was very thorough, and professionally done. You are obviously much more skilled at using the program than I am. It will take me some time to digest the techniques you showed.

    Thank you.

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