Home > computing, graphics > A Custom Drawing Projections Tool

A Custom Drawing Projections Tool

November 29, 2008 Leave a comment Go to comments

Back in 2007 I developed a software tool that could generate technical drawings in a range of drawing projections from a 3D model with emphasis on oblique (both cabinet and cavalier, as well as custom obliques), planometric, dimetric, trimetric and one-point perspective.

I could describe them all as well as many more in terms of what the projected three axis look like on the projection plane. I described them all in terms of a scale on each of the three axis, as well as the angle two of the axis make with the projection plane’s horizontal.

Description of the projection in terms of the projected view of the three standard basis.

Description of the projection in terms of the projected view of the three standard basis.

In terms of the actual development of the program I’m sure I could have done things a lot better. But I did learn a lot from the experience. The program worked to my needs and did what I wrote it to do so in that sense it was a success. The only downside would be that I did a lot of code rewriting of code that already existed out there (which probably did thinks better than I implemented them). Although since then I have done much more programming and had formal training so have learnt about better methods and practices.

The approach I took was basically import a DXF file, process the data to change its projection, and then export it as a DXF again. I used 3D polylines generated from my 3D model in Rhino and saved as DXF for the input. So I had to write a cutdown DXF reader/writer, as well as a way of storing this data internally and then doing the transformations on it then exporting it back into DXF so I could open it up in AutoCAD.

I only supported points, polylines, circles and arcs as this is basically all that Rhino exported from my model. To simplify the process of circles and arcs I internally converted them to a bunch of polylines as only for some projections they stayed as nice ellipses.

The user interface of the tool.

The user interface of the tool.

From a very simple model in Rhino, I use the silhouette tool to create the polylines which once impororted into my program produced the following samples.

Cabinet Oblique

Cabinet Oblique

Cavalier Oblique

Cavalier Oblique

Planometric

Planometric

One Point Perspective

One Point Perspective

There is also a range of built in axonometric projections…

A range of axonometric projections are built in.

A range of axonometric projections are built in.

Finally here are some of my production drawings (from my 2007 HSC ITG Major Work (photos here)) that I used the software to create.

Oblique

Oblique

One Point Perspective

One Point Perspective

Planometric

Planometric

Trimetric

Trimetric

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  1. John
    July 27, 2009 at 11:54 am

    so can u share with us?
    a very useful tools indeed~~~~

    • Andrew Harvey
      July 27, 2009 at 12:21 pm

      Yes I can, but…
      The source code is really really really bad. It goes against everything I have since learnt in uni. Its not all that robust, while simple things worked like in the pictures I showed here, when I gave it something really complicated it failed. It was just an experiment for me, something I could try when doing a school assignment.

      Also most of the work is actually reading the source file and writing the output file (and also converting circles and ellipses into many line segments). The actual transformation is just one simple matrix multiplication, but things like AutoCAD couldn’t seem to do that for me.

      It won’t remove hidden lines either (because it will only accept wireframe’s as input).

      If you still want it that is fine, but do you want the source (I did it in Visual Basic 2005) or executable?

      Oh and also I wrote some commentary about this for my assignment, you can get that from, http://www.mediafire.com/?jqn4ln2tn2l. (It’s in Appendix A I think). Also those drawings above are available from http://box.net/andrewharvey4, the ITG_MajorProject_2007 files are the ones for that assignment.

      Also I’m curious where is your source data coming from?

  2. October 5, 2009 at 4:50 pm

    Hi,
    My name is Matias and I’m teaching an architecture studio at Otis College of Art and Design in Los Angeles.
    I need my students to show their 3D models in the view that your site calls “Cabinet Oblique”.
    They all use Rhino, Autocad and Max but none of those programs shows you a model with that kind of view.
    Your Viewit software seems to do exactly that.
    Can you please tell me if they can download it and if so, from where? I tried the link to MEDIAFIRE but it didn’t work. Thanks
    Matias
    310 869-6336

  3. October 21, 2009 at 4:48 pm

    Thanks for sharing this software with me and my students. I understand you moved on and don’t want to hear much about problems with this program.
    However, my students and I spent a good 40 combined hours trying to get a “cabinet projection” of a simple model and failed. The closest we got was a DXF file that that looks like a point on the Autocad screen. When selected, you can see that it’s not a point but many entities but it doesn’t let you zoom in or scale it up.
    If you have a quick tip to share with us, we’ll greatly appreciate it. If not, we’ll have to give up.
    Thanks anyway. MC

    • Andrew Harvey
      October 21, 2009 at 8:32 pm

      Try it on a simple model first (eg. a cube) and make sure it works as you want it there before feeding it a more complex model.

      These are things you probably tried, but is the model coming from Rhino or AutoCAD? And are you exporting the lines/arcs (not surfaces) to an old DXF format (use R12)?

      A video showing it in action is up at http://vimeo.com/7179885 but it probably won’t help. Its only in the 2nd half and really sped up, so if you are really keep you can download the mov and slow it down.

      • Beppe
        August 17, 2012 at 5:16 pm

        Hi Andrew,
        this is a very interesting tool!
        Even today, I think there are not many ways to set a “Cabinet Oblique” view in Rhino or Autocad.
        Is the tool still downloadable somewhere? I really hope so. The old links do not work anymore (Forbidden Access).

        • Andrew Harvey
          August 17, 2012 at 7:31 pm

          It’s nice there is still interest in this, but I don’t think it would be very useful.

          I really recommend you implement this yourself. It really isn’t that hard.

          I wrote some documentation for this at http://tianjara.net/hsc/itg-major-work/ITG_MajorProject_2007_ManagementFolio_Jul09.pdf page 194 and onwards.

          • Beppe
            August 18, 2012 at 11:24 pm

            Thanks for the documentation.
            Unfortunately I’m not able to programm this kind of tools.
            Thank you anyway.

  1. November 29, 2008 at 1:01 am

I don't read comments anymore due to an increase in spam comments. If you want to get in touch please send me an email (see tianjara.net for details).

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