use a picture as a starting point

by Nate Hekman on April 9, 2008

If you’re starting a new project and you already have a picture of the geometry, you can get started quickly by using that picture as a reference for drawing your geometry. 

The picture may be from another CAD application, or even a photograph or a hand drawing as long as it’s accurate enough for your needs.  The important things are that it represent the geometry you need to analyze, and that it be to scale.

Import the picture

  • Create a new blank analysis;
  • choose Sketch – Pictures from the menu or toolbar;
  • click the Insert button and pick your picture file;
  • your mouse cursor changes to a thumbnail – click on your drawing to place the picture.  (The spot you click will be the bottom left corner of the picture, but it doesn’t really matter where you put it yet, as our next step will be to resize and position it properly.)

(See importing pictures for more tips, including converting DXFs into regions automatically.)

Here I’ve imported the sketch of a Lagoon Berm Design I found through a Google search, from http://www.ces.purdue.edu/pork/manure/dam.htm.

Importing a picture to use as reference

  

Scale the picture 

Now that we have a picture on our screen, we want to scale it properly so that GeoStudio’s coordinates match those in the drawing.

To scale a picture, you need to know the actual engineering coordinates for two points on the picture–preferably two points that are far apart from each other.

In this example, I’ll pick the top-left of the berm, and the right edge of the shelf under the water, because that’s all the sketch gives me distances for.  Hopefully in your real-life problems you have a bit more data!

Still in Sketch Pictures mode, and with your picture selected in the list:

  • click Scale…; a “Scale Picture” dialog box appears.
  • Click on one of the reference points; this will be Point A.  For my example I’m clicking the top-left of the berm.  (Zoom in if you have to, to improve accuracy.)
  • Click on the second reference point; this will be Point B.  For me that’s the edge of the shelf.
  • In the Scale Picture dialog box, type in the real coordinates for the two points you’ve defined.  I’m giving Point A the coordinates (20,20) and Point B (35,17).

Define points A and B to scale the picture 

Click Apply, and your picture is now scaled to match your file.  Double-check it by moving your cursor to other points on the picture and make sure the coordinates are correct.

Draw the Geometry

Once the picture is properly scaled, drawing the geometry is easy.  Use the Draw Regions command to draw regions overtop of the scaled picture.

Caveat for version 7.03

Unfortunately, a bug in GeoStudio 2007 version 7.03 (and likely earlier versions as well, I haven’t actually tried them) broke picture scaling.  To use this feature you’ll need version 7.1 or higher (which has not yet been released as of this writing but I hope it will be soon), or version 6 (GeoStudio 2004) or earlier.

With 7.03 you’ll have to instead scale the picture by hand:  use the Modify Objects command, select the picture, then drag the corners to resize it until your reference points end up at the right coordinate.

{ 0 comments… add one now }

Leave a Comment

You can use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>