michael f. berg

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  • michael f. berg
    Participant

    Dear Bryan,

    are you familiar with MS-EXCEL?

    Then you could try this:
    Put stations (View->Intersections), click on the left most icon, where you want to know the knuckle points. In “Display” switch on only the stations. Then File->Export->DXF 2D Polylines, MARK Create individual files.
    Use edit to read and understand what is written in these files.
    The DXF-format is readable for humans even if it is very lengthy…

    Write a short Basic, Pascal, Java or whatever you like program to convert the DXF-File into a *.TXT having only the co-ordinate information in x,y,z always in one line.

    Import this into an EXCEL-table. So f.i. you will have x-values in Col A, y-values in column B, z-values in column C.
    In Column E calculate the successive differences of column A. I.e. in E1 you write
    =A2-A1, in E2 you write =A3-A2 and FILL the column E downward as longs as there a numbers in columns A,B,C. Then copy Column E to F and to G.
    What you have done then is to calculate the tangent vector to your station.
    Knuckle point have a JUMP in the tangent, haven’t they?

    Now do a similar procedure in column I: I1 contains =E2-E1, I2 contains =E3-E2;
    Simply copy column E to I, J and K.
    Now you have sort of the second derivative of A,B,C in columns I,J,K.

    In column M write the following: In M1 =sqrt(I1^2+J^+2+K1^2). Fill downwards to the end of all numbers. This is the absolute value of the curvature of your station, and it must be big at knuckles and quite small in between.
    So column M gives a MARK every where in A,B,C is a knuckle point.

    Actually you can also write a second Basic, Pascal or Java program reading in the *.TXT file line by line and -forgetting nearly collinear points- writing only knuckle points to a new *.txt file: Thats what you would prefer, I guess.

    Try it and don’t hesitate to ask for more help if necessary.

    Kind regards
    michaelf

    in reply to: Gallego #35436
    michael f. berg
    Participant

    Dear Gallego,

    in the main menu you find the submenu “View”. The last item there is “Toolbars >” and it is here where you can switch on and off all of the toolbars.
    (This is only because the language of the forum is English.)

    Alora:
    En la barra principal del programa Delftship tienes el menú “Ver”: El mas bajo punto abajo “Ver” esta “Barras de herramientas >” y aquí puedes activar o desactivar las diferentes barras…

    Kind regards

    michaelf

    in reply to: Show me your ships! #35419
    michael f. berg
    Participant

    Hi, Icare,

    for some years I did white water canoing with a kayak somewhere in Bavaria, Austria and Switzerland. So I am much interested in your kayak development.
    My son actually is kayaking on the Baltic Sea, but he relies on his arms, not on a rigg, even when crossing from Sweden to Finland…
    The problem of the rigg being in sight of the man at the steering wheel is very old: but he is not alone on the ship. These yard sails under the bowsprit in use up to the 17th century were called “blinde” because they made the man at the rudder blind.
    It is a more ore less theoretical problem.

    As an answer to your nice Canadair-like water planes: For many years I plan to make a flying model of the “Dornier Whale” used by Roald Amundsen to fly to the north pole. The story is most interesting but it seems not to belong in the D.S. forum…

    Thanks for your answer
    michaelf

    My next model in Delftship could be a Dornier Whale

    in reply to: Show me your ships! #35412
    michael f. berg
    Participant

    Hi, everybody:

    I guess it was the *.bmp extension the forum didn’t like…

    Demo1.jpg

    Demo3.jpg

    Demo2.jpg

    in reply to: Show me your ships! #35408
    michael f. berg
    Participant

    Hi everybody:

    Just a PS containig some more pictures…

    Kind regards
    michaelf

    in reply to: Show me your ships! #35395
    michael f. berg
    Participant

    Hi everybody,

    here is my last – still unfinished- model. (An Arab saying is: When the house is complete the owner dies. So leave things uncomplete!)
    The ship is an “Schebecke” of algerian corsars of the 18th century.
    This “Latin” Rigg gave them crucial(!) anvantages over yard rigged ships.
    They could go much higher to the wind and easily and quickly could go through the wind…
    Data are extracted from Fredrik H. af Chapman “Architectura Navalis Mercatoria” of 1764. Reprint edited by Delius, Klasing & Co, 1984.
    The Rigg is taken from Marquart: “Bemastung und Takelung von Schiffen des 18. Jahrhunderts”, VEB Hinstorff Verlag Rostock, 1986.

    I know this is not the use Delftship is made for, but I love the program and have learned now by extensive use of export and import to get what I want…

    Have a good time all together

    michaelf

    in reply to: Best way to create bulwarks etc. #35394
    michael f. berg
    Participant

    Hi, Sean:

    I don’t know if it is the best way, but try the following:

    Shift the points of the controlnet so that you can CREASE the edges of the planned bulkwark on your hull. It might be helpful to tools->markers->import from a handwritten text file (see manual!).
    Display inner edges, select the inner edges of the planned bulkwark (ctrl-select), add a new layer and move the faces of the planned bulkwark to the new layer. Export the new layer as part, f.i. as “bulkwark.part”. Edit undo every thing so your hull is in order again. Save and close your project for a moment.
    With open and cancel produce an empty working space, and into this import your recently created “bulkwark.part”.
    Now f.i. your bulkwark shall protrude say 2 inches from the hull in all directions.
    The length of your hull is maybe 100 feet equals 1200 inch. The half beam of your hull is 12 feet equals 144 inch. Now scale your skinny bulkwark for x direction by a factor of 1 + 2×2 inch/1200 inch (= 1.0033). Scale the bulkwark in y direction by a factor of 1+ 2 inch/144 inch (=1.0139). Because in scaling the zero point is fixed you have to move back now your bulkwark by 2 inches.
    Edge extrude the bulkwark inward by y = -2 inch.
    This scaling procedure is not quite exact actually, but it works better than free hand adjusting…
    Export it again as part “bulkwark.part”.
    Close the working space and open again your old project. Import “bulkwark.part”,
    it comes to a new layer. Do exclude it from the hydrodynamics and give it a suitable name and colour…

    Kind regards michaelf

    in reply to: Include markers in transformation in 4.46.158 #35289
    michael f. berg
    Participant

    When nobody gives you an answer you have to find it yourself.

    First: The program- now DSpro- in version 4.46.158 does offer to transform the markers together with the whole ship again. I don’t know why, but I am glad it does.
    Nevertheless I found, it does not make sense to readjust e.g. the stations in a rotated model to the rotatede markers of model.
    Simply try it: The new stations or waterlines do not correspond to the rotated markers. Logical, actually.
    So in case you feel you have to do readjustments: rotate the whole ship back, do the readjustments and re-rotate again…

    The “subdivide controlnet” problem- to limit subdivision to a single layer- you can still now solve by exporting the layer as part, closing your actual project, importing it to a new (empty) model, do the subdivisions there, export it again as part, closing the new model (without saving), opening your actual project again, reimporting the layer:
    Dear Marven, this could be simpler, if you allowed to limit the order “subdivide controlnet” to a single layer…

    I still would love to have the measuring capability…
    Perhaps you could provide as an read-only-interface simply as pipe or a stream where the coordinates which show up in a window when you select a point are listed…

    The extruding from closed edges-on your own risk- can be done by..Oh, if somebody wants to know I’ll explain how. Just let me know…

    Thanks to Marven and to everybody else for your patience

    MichaelF

    PS: Personally most I’ve learned from Dida’s questions and Marvens answers. ¡Muchas gracias!

    in reply to: Control points on an arbitrary plane #35281
    michael f. berg
    Participant

    Hi Petter:

    If you do it axis by axis the number, you put in, is the angle in degrees and the rotational direction (looking into the direction of the respective axis) is counterclockwise for positive angles.

    If you put in more components at once- say rx, ry, rz- the rotational axis has the direction of the vector (rx,ry,rz). If you look into this direction the rotation will be counter clockwise with the amount sqrt(rx²+ry²+rz²). This (rx,ry,rz) is therefore called an “axial vector”. My 3D imagination is not good enough, so I prefer to do it axis by axis.

    In your case you did a rotation around an axis pointing (-25,-15,0) by an angle of
    sqrt(625+225)=29.15… degrees counter clockwise, OK?

    Have a nice day…

    michaelf

    in reply to: Control points on an arbitrary plane #35273
    michael f. berg
    Participant

    Hi Petter,

    I am happy you succeeded.:)
    By the way:
    When I wrote “rectangle” I meant “rectangle” not “box”. A box consists of six rectangles, of which 5 are not useful for our problem.

    Make layer 1 the active layer to accept the next input:
    Edit–>Point–>Add
    Delftship suggests (0,0,0) in the co-ordinate window.
    Insert for x -2
    Edit–>Point–>Add
    Delftship suggests (0,0,0) again in the co-ordinate window.
    Insert for x -2
    Insert for y 4
    Edit–>Point–>Add
    Delftship suggests (0,0,0) again in the co-ordinate window.
    Insert for x 5
    Edit–>Point–>Add
    Delftship suggests (0,0,0) again in the co-ordinate window.
    Insert for x 5
    Insert for y 4
    Look at the four newly generated points in the perspective view
    Keep the CTRL key pressed
    Select in counter clockwise direction the 1st, 2nd, 3rd, and 4th point
    Edit–>Face–>New
    You see a sort of ellipse.
    Select one after another without CTRL the four points and set the corner property in the co-ordinate window.
    Then you have a rectangle, flat and 2 dimensional…

    In intersecting layers
    the first layer, where you want the new points inserted (here layer 0), must have a fine control grid. The fineness of the one where you take the cut from (here layer 1) does not matter.
    This is because only the edges of the first layer are tested where they dissect the faces of the second layer.

    Oh, please, try this as well: I love to be right.:)

    We are learning every day by doing and
    we learn from examples and counter examples and from errors.:lol:

    Kindest regards
    michaelf

    PS: I do the rotations separately first for the x-axis then for the y-axis.
    One funny thing about rotations is: The result depends on what you do first.
    Try it with a dice…

    in reply to: Control points on an arbitrary plane #35268
    michael f. berg
    Participant

    Hi Petter,

    it can be done in this world:
    Shortly you have to EDIT–>POINTS–>INTERSECT LAYERS the shiphull in one layer with a properly inclined PLANE in a second LAYER.

    Step by step:
    Try it out with the “NEW” Model:

    Add a second Layer,

    Produce there the rectangle (-2,0,0),(-2,4,0),(5,0,0),(5,4,0).

    TRANSFORM-_>ROTATE…(only the second layer!!)
    Insert for the tranversal axis -10 degrees, for the longitudinal -25 degrees.

    TRANSFORM–>MOVE…(only the second layer!!)
    Insert for the vertical translation 0.55 m.

    Now TOOLS–>SUBDIVIDE CONTROLNET, possibly twice.

    Switch to the coloured Mode. You can see your flat plane now intersecting the hull.
    Adjust it by the proper TRANSFORMS till you like it. Then
    EDIT–>POINT–>INTERSECT LAYER
    Select insert new points on Layer 0, intersections with layer 2.

    Switch off Layer 1 now. On the hull in Layer 0 you see in yellow the edges of your
    plane intersection.
    First do an EDIT–>EDGE–>CREASE and ESC. The new edges must be red now.

    Then edge by edge delete the internal faces and insert new faces by selecting
    the proper points on the red edges and EDIT–>FACE–>NEW.
    You must then again CREASE the edges of your new flat plane.
    Look at it in chromium plated presentation…

    I hope this was not to lengthy.

    Kind regards= michaelf

    PS: Remember: TRANSFORM–>ROTATIONS always go around the point (0,0,0)!!!

    michael f. berg
    Participant

    dxf-files are (lengthy) plain text. So use f.i. edit to look into it. I have written a delphi program to extract the polyline vertices and possibly the 3Dfaces in a form readable by MS-Excel. There you can do more…

Viewing 12 posts - 1 through 12 (of 12 total)