Maxsurf question : how to fillet edge of 2 bonded surfaces

Discussion in 'Software' started by Justinet, Jun 27, 2019.

  1. Justinet
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    Justinet Junior Member

    Hello everyone,
    What is a good way to fillet edges of 2 bonded surfaces with Maxsurf ?
    I have not found any specific tool to do this.
    I would like to obtain a good result such as on the cover images of these videos :
    Steve Crook at Solent University https://vimeo.com/user25704095
    with a large fillet along the sheer line between deck and hull
    I have gone thru these videos up to lesson #7 but it doesn't tell how to do so !

    Thanks a lot for your help
     
  2. TANSL
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    TANSL Senior Member

    Try yo make your 3D model with Rhino and then export it into Maxsurf. That's what many people do because modeler in Maxsurf is not very frienfly.
    Anyway, could we have your msd file?
     
  3. Justinet
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    Justinet Junior Member

    Thanks but i'd like to know how to do it with Maxsurf alone, just to replicate the model on a.m. videos as an exercise at this stage, and also because i have had a lot of problems with Rhino exports to Maxsurf, while
    it seems much easier the other way around from Maxsurf to Rhino.
     
  4. TANSL
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    TANSL Senior Member

    "fillet edges" does not exist in my Maxsurf version. May be "Bonding Surfaces" (see Modeler Manual in pdf format) could spolve your problem.
    And you're right, exporting files from Rhino usually gives very frustrating results. I make the models in AutoCAD and export them in .igs format to Maxsurf.
     
  5. bhnautika
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    bhnautika Senior Member

    Justinet as Tansl has said, look at bonded edges,there are two possible ways to archive what your after in maxsurf ,either with two surfaces or three. Both require you to use the tangency when bonding edges.
    Importing into maxsurf from rhino is ok if you follow the rules, no trimmed surface, no planar curves surfaces, surface edge points must match if you want to bond them. Also maxsurf only want one side, model should sit on a zero centre axis.
     

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  6. Justinet
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    Justinet Junior Member

    Great, thanks !
    Using the tangency while bonding edges looks like a good solution
     
  7. Justinet
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    Justinet Junior Member

    Hi there,
    Any suggestion on how to get a fillet along the intersection line of 2 trimmed surfaces this time, again by using Maxsurf only ?

    I followed your advice and managed to get a nice fillet between hull and deck which are 2 bonded surfaces, but it seems (i am starting to use Maxsurf and have a lot to learn !) more difficult with trimmed surfaces.
    In this last case i cannot use bonded surfaces and hence used the trim tool.
    Many thanks again for your help
     
  8. bhnautika
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    bhnautika Senior Member

    Justinet maxsurf is not a general CAD program even though its getting a few of those basic features for generating surfaces, it is limited. Maxsurf was designed as specialist software to create hulls and general components for analysis and construction. Detailed parts were to be done by other general CAD software. What you are after is a little to much detail for maxsurf.
     
  9. Justinet
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    Justinet Junior Member

    Hi bhnautika and thanks for your reply. I understand most people just develop a basic hull on MaxSurf (MS) and then move to Rhino or other CAD softwares. The reason i am trying to learn MS and design a more comprehensive model
    directly on MS is to be able to freely use the other MS modules such as Resistance, Stability, Motions, etc for analysis. I had not managed to actually use imported Rhino models (though simplified and following the guidelines, or using a plugin) , perhaps due to my poor knowledge of MS.
    I also believe MS tend to yield fairer surfaces faster than e.g. Rhino, despite the fact i am always endeavoring to using the min number of control points.

    Coming back to my "fillet" question, not so important when above DWL (the good looking deck to hull fillet was just an exercise to learn and replicate what i had seen on a.m. videos from Solent Uni), but more important to get
    an idea of potential impact on eg resistance when below DWl.

    I have an idea of a pathforward to get a fillet between trimmed surfaces, but do not know how to actually do it with MS !
    Would take a minute with Rhino but then the import which will include filleted and trimmed surfaces won't work on MS.

    Would envision :
    step1 : copying the intersection (between the 2 trimmed surfaces),
    step2 : project this curve to the 2 surfaces at an offset distance e.g. 50mm for a 50 fillet radius,
    step 3 : trim the 2 surfaces with these curves and then
    step4 : sweep a curve (an arc with the same radius or more likely a curve tangent to both sides) to get the fillet surface in-between...
    step5 : and then bond (with tangency) these 3 surfaces together to make sure it's continuous ??

    but i so far haven't found out which MS tools to use for processing !?

    First steps : 1- Fit curve to contour, 2- Duplicate curve with spacing

    seen a curve can be used for trimming but i am stock here, how to project the offset intersection curve on the appropriate surface and get it trimmed ?
     
    Last edited: Jun 30, 2019
  10. TANSL
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    TANSL Senior Member

    Making a very accurate 3D model in Maxsurf will not help you in any way to understand how that application works and I can assure you, from my own experience, that the results of Maxsurf will vary very little between a good model and a very good one. Nowadays it is vitally important to be able to create a 3D model good enough to be able to extract data from it. But it must be a correct model, in each case, for what you want to obtain. The designer must assess which is the correct model, neither the best nor the least good, but enough for each application. And, on the other hand, you must use the most suitable application for each calculation. We are many who use Maxsurf for calculations of naval architecture (which in that is unsurpassable) and for everything else we use other applications.
    In summary, my advice is that it is not worth making a perfect model with Maxsurf, it does not teach you anything and, coinciding with what bhnautica points out, the Maxsurf modeler is very disadvantaged in relation to other CAD / CAM programs. Measure your efforts and do not waste energy on what is not worth it.
     
  11. TANSL
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    TANSL Senior Member

    In Maxsurf'´s "ModelerManual.pdf" you can find examples, which, perhaps, will help you get what you are trying to do in Maxsurf. Specifically, the chapters "Bondig surfaces" and "Control Point Weight Concept" may give you ideas and tools to achieve it.
     
  12. bhnautika
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    bhnautika Senior Member

    Justinet two possible work arounds. One, take model out of maxsurf into rhino or other. Create fillet,then export the fillet surface (no trimming ) back into maxsurf.
    Two, use the extrude surface in maxsurf to create the third surface between the two surfaces, shape that to a fillet and trim in maxsurf. I used the yacht model that comes with maxsurf to fillet keel/hull joint. fillet import.png
     

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  13. Justinet
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    Justinet Junior Member

    Great, thanks very much !
    Re solution #2, how did you get this third extruded surface ? (i am ok then to reshape it and trim)
    When i use the intersection line between the trimmed surfaces (e.g. "fit curve to contour" tool to make a copy) i get a curve with far too many points (havent seen a tool to simplify that curve) hence yielding an unworkable surface.
    In your example between hull and keel how did you get the curve to be extruded and which extrusion (eg transverse , vertical ?) did you use to get this third surface ?
     
  14. Justinet
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    Justinet Junior Member

    I am sure you are right. I just want to analyse a few things under the hull. If it doesnt make any difference on resistance i 'll stop doing it. So far from the few tests run i must say i get once imported from Maxsurf into Rhino very nice and fairer surfaces thanks to the MS modeler while at the same time getting hydrostatics, stability, resistance, etc
     

  15. bhnautika
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    bhnautika Senior Member

    Justinet using the yacht example, I first un-trimmed the keel, selected the control points at the top of the keel and moved them down to below the hull. Then select the top edge, then go to “surfaces- extrude surface- input distance, in this case vertical”. This will give you straight surface from the original surface edge, you then add another set of control points about mid way to the new surface. Go to surface properties for the new surface and change name, the stiffness(example 2 to 3) and to nurbs if you wish. You can bond these surfaces but without tangency . If you want tangency you will have to add another line of control points to the keel up near the top edge to mirror the mid points of the fillet surface.
     
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