Problems with stability of trimming in Maxsurf Modeller V22 update 1

My models keep losing their trim when I move surfaces even slightly. Also after saving an exiting, then reopening the model the trim is all screwed up. This is very time consuming and frustrating, not what I would expect from such an expensive and high end programme

Also the application now always starts with trim set to visible which isn't a major problem but being able to change this would be good.

  • - reduce the number of surfaces in each surface cutting list. In the surface properties, go to Cutting Curves and Surfaces. Deleselect any surfaces that you aren't using to trim that surface.

    Using one of Glenn Shaw's models and reducing the surfaces to less than 20 by removing all the superstructure and some other details I found that the application often ignores the cutting surface list when recalculating the model.

    This occurs after changing the cutting surface list for another unrelated surface, adding a frame or a new surface etc..

    Most times the trimming can be corrected by selecting incorrectly trimmed surface and viewing it's cutting surface list and clicking on OK.

    In general I have found that if the model contains more than 5 or 6 surfaces then you start to have issues managing the trimming.

    MAXSURF modeler  Advanced is supposed to support unlimited surfaces yet in the last couple of major releases (20, 21, 22), it's key features start to fail if you have more than a dozen surfaces in your model.

    As a general response; The dynamic trimming used by MAXSURF is fantastic if you are moving and fairing surfaces because the surfaces always stay trimmed to the intersections. However, if MAXSURF looses track of which regions are trimmed and which regions aren't, then it becomes quite annoying.

    It would appear that since at least version 20, MAXSURF has had a lot of problems keeping track of which regions are trimmed. As having the surfaces trimmed correctly is required for correct part generation and analysis (admittedly much of the hydrodynamic analysis can be done with a simplified model but not the part generation)  it is a significant bug with the current releases. Note that there was no issue with trimming these models in the version of the software that they were originally created in.

  • Hi Glenn,

    I have responded to your service request on this. It would be great to take a look at your model.

    As a general response; The dynamic trimming used by MAXSURF is fantastic if you are moving and fairing surfaces because the surfaces always stay trimmed to the intersections. However, if MAXSURF looses track of which regions are trimmed and which regions aren't, then it becomes quite annoying.

    Here are some general hints on how to make your trimming more robust:

     - avoid shallow intersections between surfaces that you are trimming. It is difficult to numerically find the point where the two surfaces meet and small computer rounding errors to numbers or changes in precision can make large movements to the location of the trim intersection.

     - reduce the number of surfaces in each surface cutting list. In the surface properties, go to Cutting Curves and Surfaces. Deleselect any surfaces that you aren't using to trim that surface.

    - Use a trimming curve instead of a surface. If you don't actually need that surface (for instance a transom), then use a trim curve. That way you won't need to trim the transom to size too.

    And as a final option, consider a different surface layout instead of trimming. For example, instead of adding a square deck and trimming it to the hull surface, try extruding the edge of your gunwhale using Surfaces | Extrude Surface.

    Regards,

    James