Marven

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Viewing 15 posts - 1 through 15 (of 552 total)
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  • in reply to: how to import and read correctly a vrlm model. #43761
    Marven
    Keymaster

    VRML is really not a preferred format when it comes to  importing a hull. I would advise to use the iges format, or if all else fails STL.

    in reply to: Export Offsets again) #43599
    Marven
    Keymaster

    Hi John,

    For skinning the geometry of the stations would be sufficient.

    Enter the points of the stations (bottom to top, aft to front) in a text file and use the “Import surface” to import it into DELFTship. DELFTship will try to fit a surface through the stations, and in most cases the results will be more pleasing compared to those of the table of offsets.

    See also the enclosed file. The format is described in more detail the manual, but the first line indicates units are in meters. Then for each station the x,y and z coordinates are specified from bottom to top. An empty line is used to indicate the end of a station. EOF marks the end of file.

    • This reply was modified 10 months ago by Marven.
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    in reply to: Export Offsets again) #43596
    Marven
    Keymaster

    This is correct as far as it goes but you failed to consider the buttock co-ordinates, without which the loftsman would, in many cases, struggle to obtain the correct underwater shape of a vessel. Even in the days of working from half models, they often used two models. One sliced horizontally at the waterlines and another sliced vertically at the buttock lines.

    Hi John,

     

    You are correct. By introducing buttocks in addition to waterlines and stations you will end up with quite a few triangular and/or 5 sided faces. This will make it very hard to make a fair hull surface, that’s why for most hull shapes this method won’t work.

    I was looking at the Uffa Fox lines plan and noticed it has a canoe stern and (near) vertical bow. Have you considered using just the geometry of the stations by using the “Import surface”  feature?
    This will use a technique called “skinning” to create the hull surface in DELFTship. I expect the results to be a lot more usable.

    • This reply was modified 10 months ago by Marven.
    in reply to: Export Offsets again) #43543
    Marven
    Keymaster

    Hi John,

    Thanks for sharing your files with us. The problem with a table of offsets is that it contains only a limited number of points,  the intersection points of stations and waterlines. For the mid ship area this  is mostly just fine, but for the (curved) ends of the vessel it means a lot of information required to build a 3d model is missing, such as where a station (or water line) ends at the stem or keel for example. Traditionally this information was filled in by the loftsman who recreated the linesplan on the lofting floor. This lack of information can sometimes be fixed by adding more stations/waterlines.

    Another problem is that a sheer line with high curvature means that waterlines close to deck level are split in 2 (aft and forward parts). This is not captured correctly by a table of offsets.

    In other words, tables of offsets are often not very suitable to creating 3D models. Other options (such “import surface” or “import chines”) are better suited to the task.

    in reply to: Export Offsets again) #42889
    Marven
    Keymaster

    Hi John,

    Re problem 1:
    The recurring 1.300 value looks very strange indeed. Can you please send us the DELFTship model which you have used to create this file so we can use it to debug the software?

    Re problem 2:
    I suspect this issue is related to the first. We’ll investigate this as soon as we have received your file so we can address this issue before the next update.

    in reply to: Delft Ship Installer – Version 11.10 – Corrupted? #39539
    Marven
    Keymaster

    Hi,

    It seems that Windows smartscreen is preventing the installer to start after the download because there is no publisher certificate present in the installer.
    Have you tried downloading manually from the download area and then start the installer manually?
    This seems to work for most users.

    Sorry for the inconvenience.

    in reply to: Model Database #39443
    Marven
    Keymaster

    As long as you make sure both versions are installed in a separate folder you can install the free version alongside the pro

    in reply to: Model Database #39437
    Marven
    Keymaster

    Hi Jesus,

    The models are no longer available through our website, only through DELFTship where you can directly browse, search and download the models.
    You could try downloading the free version to download the models and saving them to your current version of DELFTship. Make sure not to upgrade the file version to the latest otherwise your copy of DELFTship won’t be able to open the files.

    in reply to: Face Normals Get Flipped When Collapsing Edges #39359
    Marven
    Keymaster

    In most cases when the software orients the normals incorrectly this is caused by incorrect geometry. For example there could be edges in your model with more than 2 faces connected to it (in which case the edges turn either purple or green), or even a double face (2 faces using the same points).
    If this is not the case please send us your model so we can have a look at it, as perhaps we might need to improve the algorithm which checks for the orientation of face normals.

    in reply to: Apparent Discrepancy in Displacement (Free, Imperial) #38747
    Marven
    Keymaster

    We have investigated this, and we indeed found a bug in scaling the layer thickness when switching project units. We wll fix this as soon as possible.

    You are using the actual layer thickness in your hydrostatic settings, so as the layer thickness is not scaled correctly your hydrostatic values will change.
    I also noticed that your appendage coefficient is set to a very small value (0.125) and that the layer thickness of the hull is set to 0.80 meters. So you have a very, very thick outer shell (80cm) but then multiply your displacement with a value of 0.125, thus accounting for only 12.5% of the calculated displacement. Generally your appendage coefficient should be close to 1.0

    in reply to: Resave the old version FBM #38700
    Marven
    Keymaster

    Only if you have the professional edition.

    in reply to: Exporting Sections #38656
    Marven
    Keymaster

    There should be a dropdown list at the bottom of the window where you specify the file name. The drop-down list is labeled ‘Save as type’

    in reply to: Exporting Sections #38654
    Marven
    Keymaster

    Hi Will,

    When exporting to DXF, make sure to use one of the later dxf versions, but not R12.
    DXF R 12 automatically converts all spline curves to polylines as Autocad R12 did not support splines. The polylines are simply lot of (connected) smaller straight line segments. Splines are smooth curves through the original points, which is what you want.
    Both later versions of DXF and the IGES curves export however should give you smooth curves.

    in reply to: document publisher #38639
    Marven
    Keymaster

    Dear Jochum,

    That feature was added in version 8.15.299. It seems you are still usng version 8.13.298.

    in reply to: Offsets Export/Import #38550
    Marven
    Keymaster

    Hello Jurgen,
    Still nothing from Mission Control regarding offsets!

    Mission control is currently looking into this.

Viewing 15 posts - 1 through 15 (of 552 total)