Using just a small image with some dimensions on it, and written clues from the product’s literature, a decent representation of a fairly complex model is possible.
I’ve used this technique since I first started using Inventor, and believe it is a hold-over of sorts (modified for Inventor) from my AutoCAD days. At any rate, I used to have to employ this technique far too often in my early days in yacht design. We gave our vendors some slack back then as 3D modeling was still newish to a lot of companies.
Flash forward five years, and it seems as though time has stood still. Finding models of anything outside of mechanical design world (also pretty limited) is still almost impossible. The polygon prop models used generally for architectural rendering do not count as they are, for the most part, unusable in a digital prototype (BIM).
As I stated in the first article, BIM Models Via Reverse Engineering With Autodesk Inventor – Part 1, all I had to go with for this model was an image with a few dimensions. I also knew from the text description that the larger plumbing connections were 4” and that the drain was a tapped hole for a ½” I.D. hose barb. In this case, that should be good enough.
The Reverse Engineering Technique
Firstly you will need start a new part file, and create a sketch on the XY plane (or whatever plane you would normally use as an elevation). Go to the Insert panel on the Sketch tab and select the Imagetool. Browse to the image of the drawing you need, and double click it. You will now have a corner of the image attached to your cursor —attach the image to the centerpoint.
Your image at this point needs two constraints. There is a construction line at the perimeter of the image….use a Horizontal or Vertical constraint on one of them to lock the image at a right angle. Now, use the Dimension tool on either of the lines again, and whatever the dimension winds up being, just leave it as-is for now. You should have something along the lines of the image below…
…and your status bar should read “1 dimensions needed”. The status bar is lying in this case as there are no further dimensions possible. The image will resize proportionally when the single dimension is altered, and an image is presumed rectangular, therefore it does not need, nor will it accept both a Horizontal and Vertical constraint.
Resizing the Image
To resize the image accurately, pick any of the dimensions on the image and zoom in on the leader lines, creating your own lines over the images lines. Set a dimension between your lines…
That’s it for today. In the next post we’ll get into the modeling. see you then….
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