Terrance Egolf

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  • in reply to: Modelling a flat bottom chine tug hull (WWII TID) #44650
    Terrance Egolf
    Participant

    Paul,

    For modeling from existing drawings or dimensions, I’d go with using full-sized dimensions, since things like the waterline and draft are already known. Also, you can use positions and dimensions in full-size units right off the reference drawings instead of having to calculate the scaled quantities.

    If you are designing your own hull and those characteristics are not known, then you would probably  still  want to go full-size so you can use the program to determine them. Trying to do hydrostatic calculations for a 1/16 scale model would introduce all kinds of errors due to the mismatch of scale between desired model dimensions and the actual properties of water used to perform the hydrostatic calculations. I’m not a naval architect, but that would seem to be a problem.

    Terry

    in reply to: Modelling a flat bottom chine tug hull (WWII TID) #44644
    Terrance Egolf
    Participant

    Here is the fifth file. Please read the first PDF. It includes all the appropriate attributions and disclaimers for this tutorial. I take responsibility for any errors or inaccuracies, since these files were written more than a year ago.

    Terry

     

    Attachments:
    in reply to: Modelling a flat bottom chine tug hull (WWII TID) #44639
    Terrance Egolf
    Participant

    Hello, Paul.

    It sounds like you are asking for some assistance in setting up background images for your model. Are you working from pre-existing plans or are you wanting to create your own plans from WW II images?

    I will provide you five files constituting a tutorial for setting up background images in DELFTship Free. I originally created these for my fellow members of the Model Ship World forums. Hopefully, you will find them useful.

    The only detail I know I have omitted from the tutorial is that, for intersections to be visible in a model file, you must check “Intersections” for the layer(s) in which a particular intersection can be visible. This selection is made in the Edit window of the Layers Menu Group. Generally, if you make intersections visible for the entire hull itself, then they should be visible for the purpose of aligning any of the background images for the model.

    The first four Tutorial files are attached here. The fifth file is in the next post (forum limitation).

    Terry

    • This reply was modified 3 weeks, 6 days ago by Terrance Egolf. Reason: Added content
    Attachments:
    in reply to: Can’t figure out how to model the back #44624
    Terrance Egolf
    Participant

    Hello, Tidexon.

    I feel your pain! 19th-century sailing ships typically have very complex geometry at the stern and transom.

    For very curvy surfaces in this area, the only approach I have found that works in DELFTship is to increase the number of polygons, especially if you are trying to conform the model to existing plans.

    The downside of this approach is that you eventually need to merge the control mesh in the aft area of the hull—with many polygons—into the area of the main hull that can be modeled with fewer polygons. This creates distinct nodes at the junction of converging edges that don’t fare well with the surrounding hull.

    I have been working for nearly seven years on reconstructing the plans for a late 19th-century brigantine, the Galilee. This image shows how I had to really subdivide the stern area of the model to create the desired surface to match the existing plans:

    Hull-Control-Mesh

    As you get closer to finalizing the shape of the hull, you should add station, waterline, and buttock intersections to guide adjusting the control net. Where the change of hull shape is more dramatic, you will need to add more intersections, which is done under the Tools tab in the Project Tools menu group. In the second image, I have included station and buttock lines:

    Hull-Intersections

    When fine-tuning the hull shape, you can use all three types of intersections simultaneously. Also, the program has the option of including diagonals, which are extremely useful for checking fareness. Realize that actual ships always had to deal with hogging and other unfareness in their hulls, so stressing about a few inches/centimeters of unfareness is probably not worth the trouble.

    Hope these examples help!

    Terry

    Attachments:
    in reply to: Modeling the 1907 U.S. Brigantine Galilee #44601
    Terrance Egolf
    Participant

    Thanks, Maarten!

    As you and I have discussed before, I have found the software to be really useful for general hull modeling—much more so than the more familiar 3D modeling software such as Solidworks, the various AutoCAD derivatives, etc., that are generally available. Adding the details to the superstructure takes more work but is doable with experience and patience.

    I think you would find a market in ship modelers who want to validate old world hull plans and to create ship model structural details for 3D printing. This could be met with a middle-grade program that emphasizes hull modeling tools and de-emphasizes the stability and physics aspects. One of the biggest drawbacks of Sketchup, for example, is the fact that when you create details smaller than a certain real-world size, the CG mesh starts combining polygons and details are lost or distorted.

    One feature I would like to see added to the program is the ability to insert graphics onto the surfaces of models. When I added the ship’s name and home port to the transom, I had to create each letter as an object and then position the letters as an overlay, offset from the underlying surface to avoid bleed through. Annoying, and time-consuming, but doable.

    Transom-Names-small

    Take care!

    Terry

    Attachments:
    in reply to: Modeling the 1907 U.S. Brigantine Galilee #44596
    Terrance Egolf
    Participant

    And here is an example of the details one can model in this software. This is a combination Hyde capstan and windlass, c. 1890, that was likely carried by the ship based on contemporary photos.

    I used the Clipping feature to remove the starboard bulwark so one can see under the forecastle deck.

    For admins: I can’t remove an attached image in the Edit mode once the reply has been posted. (That’s why there are two images attached).

    Terry

    Attachments:
    in reply to: Offset surface with errors #44576
    Terrance Egolf
    Participant

    Hi jaytee.

    I just installed v. 14.20 (342) of the program and tried to duplicate your problem with my own project file. I got nothing unusual. (See the attached Print pdf.) The only difference between my situation and yours is that I have moved the midpoint of the model in Project Settings about 50 feet aft of the AP. I did this so I don’t have issues trying to move control points in the Front or Aft views, but I also only get one side of the hull in these views with Both Sides turned off.

    It may be an issue with your .dbm file itself. I suggest you submit it to Maarten so he can evaluate it.

    Terry

    DELFTship-Front-view

    Attachments:
    in reply to: Offset surface with errors #44566
    Terrance Egolf
    Participant

    Welcome to the wonderful, exciting—and unpredictable—world of the Offset Surface!

    I don’t pretend to understand the mathematics underlying DELFTship’s surface modeling engine. However, I have attempted to do the same operation on a similar hull as well as some experimenting and the results were less than spectacular or expected.

    Any location in your model’s surface where there is a fairly significant change or discontinuity in the orientation of the surface normals, you can expect some unusual behavior of this feature. For example, I have found that along the centerline of the model (y = 0), the new offset points will tend to wrap across the centerline in the –y-direction, as if the engine is trying to accommodate the average direction of the surface normals at this discontinuity.

    Elsewhere, if you have crease edges intersecting at corners , or in close proximity to each other, the resulting offset surface can be really bizarre.

    Here is my example that I faced in my brigantine model. This shows the moulded hull and transom. The transom is on a separate layer.

    Offset-1

    Next, I turned off the transom so I can just offset the hull surface by 3 inches/0.25 feet (sorry, I’m in the US).

    Offset-2

    Then I offset the selected surface (I don’t think it’s necessary to actually select the surface; the dialog has you offset the selected layer.):

    Offset-3

    So you can see the nasty details where the rail line converges on the transom.

    All I can tell you is that after offsetting the surface, you should expect that you will need to do some cleaning up especially around edges that change direction or shape.

    Terry

    PS: The program puts the offset surface in the layer at the top of your layers list for some reason, so if it doesn’t appear after commanding the offset, then look in that layer, especially if it’s turned off.

    Attachments:
    in reply to: How to get rid of unnecessary surface #44518
    Terrance Egolf
    Participant

    You are very welcome, Hrvoje.

    I have been using DELFTship for nearly six years to reconstruct the plans for a 19th century brigantine built on the West coast of the US in 1891. My grandfather sailed in her for several years conducting scientific geomagnetic surveys of the Pacific Ocean. Very little in the way of useful plans exist of this vessel. However, I have many photos taken during 1905 through 1908 of the ship documenting her scientific charter period, which have been excellent references.

    As a member of the Nautical Research Guild, I have a long-running topic on their Model Ship World forum documenting my research into this vessel. If you are interested, you can access the topic here.

    Many, many hundreds of hours have been invested into using this program—for hull modeling only—so if there is some kind of problem working with the program, I probably have seen it! Feel free to contact me directly via the messaging feature at Model Ship World if you wish.

    Best regards,

    Terry

    Colorado Springs, Colorado, USA

    in reply to: How to get rid of unnecessary surface #44509
    Terrance Egolf
    Participant

    Hello, Hrvoje.

    I took a look at your attached file and there are several issues working together to cause this problem

    First, as a general technical issue, DELFTship doesn’t handle concave corner intersections between non-coplanar surfaces well. The surface perpendicular to the corner axis tends to get dragged through the corner instead of observing the concave angle. That was the main cause of the surface you pointed out.

    However, in your model there was another issue that contributed to the problem. You created three mutually perpendicular surfaces that appear to intersect at the highlighted point:

    Tegljac-nadgradje-1
    However, if you randomly move that point, you can see that the front surface is actually separate from the other two along the vertical edge. It’s only joined at the upper corner point:

    Tegljac-nadgradje-2a

    The easiest way to fix this is delete the facing surface, then rebuild it using the six nearest control points (highlighted):

    Tegljac-nadgradje-2

    Notice that we still have the flap cutting the corner, even though the corner point at the intersection of the three surfaces is automatically designated a “corner point.”

    To fix this, you have to “reinforce” the corner using some additional edges:

    Tegljac-nadgradje-4

    One edge does a pretty good job of eliminating most of the flap. I added another point and edge directly below the corner point, since that might be a logical place for an edge in your model.

    I have found that in most circumstances, you will need a minimum of two interior edges or another crease edge to eliminate these flaps across concave corners like this.

    Hope this helps.

    Terry

     

     

     

    Attachments:
    in reply to: importing STL #44495
    Terrance Egolf
    Participant

    Maarten,

    This topic ties into a thought I shared with you by private message a while back.

    Importing and exporting models in other file formats doesn’t seem to relate directly to the main “mission” of DELFTship, which provides high-end hydrostatic and hydrodynamic modeling for naval architectural purposes. I suspect that most users of the free version of this program are probably hobbyists and modelers, where such file management would be a great convenience and not a path to extra income, and does not warrant the expense of the full software package.

    At the same time, I imagine keeping up with various 3D file formats to ensure compatibility involves a lot of programmer maintenance effort, which incurs costs to your company.

    As a nautical historical researcher, I for one would be willing to pay a reasonable fee for a plug-in that provides the ability to import and export 3D objects in other formats, where modeling certain features might be easier in different programs, such as Blender, AutoCAD, or Solidworks.

    Just a suggestion for improving an already great program.

    Terry

    in reply to: Option to select edges only #44474
    Terrance Egolf
    Participant

    Me again.

    There is really only one reliable solution to this problem: Switch to Wireframe momentarily to select the edge(s) you want.

    The selection process relies on the relative order of the objects from front to back. If the subsurface patch is “closer” to the viewer than the edge you want—even if the edge is visible—it is impossible to select the edge with Shaded surfaces turned on.

    Hope this helps.

    Terry

    in reply to: Selecting other point at same location #44471
    Terrance Egolf
    Participant

    HDJET,

    I can’t respond for DELFTship, but from my experience, dealing with this problem comes down to good layer management. Assuming you have used the Copy function to align points on different layers at the exact same x-, y-, z-coordinate, it is key that those points remain on different layers or you will never be able to separate them without moving one out of the way to see which object/layer it belongs to. Believe me, I have had too much experience dealing with that.

    It is fairly easy to simply turn off the layers associated with that point in space to isolate the control point of interest. If you have more than one object in the same layer sharing a point, then they probably should be joined along common edges as well, if applicable, so the point is truly common to the two objects.

    Hope this helps.

    Terry

    in reply to: Edge Extrusion Flips Normals #44467
    Terrance Egolf
    Participant

    Thanks, Maarten.

    I tried that feature and it corrected the normals on the cylinder example in my previous post.

    Do you know if this action always applies to objects in hidden layers? Or can you select an object and have the Check Model action apply only to the selection? The latter would be a nice feature to have if you want to just check a specific object.

    Thanks.

    Terry

    in reply to: Cannot Redo after Undo #44458
    Terrance Egolf
    Participant

    Good catch, HDJET!

    I’ve noticed that problem myself.

Viewing 15 posts - 1 through 15 (of 58 total)