Friday, November 4, 2011

DraftSight and 3D - it's all in there

Yesterday, I wrote that DraftSight's 3D capability was limited to primitives:  triangles, rectangles, and polygons.  Boy, was I wrong.

UPDATE:  I just wrote a really quick "how to" guide for DraftSight and 3D.  Click here.

For the 3D-disinclined, let me use three real-world objects to help you understand 3D CAD.

First, imagine a wire birdcage, the kind your grandmother uses for her parakeet or canary.  A birdcage is made of a bunch of wires, crossing and intertwining.  They define a region of space - the inside of the bird cage.  CAD programs define a solid object by imagining the surface of it as a bird cage - a bunch of wires crossing each other or connecting with each other.  CAD programs just store all the wire crossings, or vertices (singular vertex, plural vertices), and the wires, or edges, that go from one vertex to another.  You've probably heard of wireframe models or drawings.

Second, imagine a fishnet - a giant fishnet, being dragged through the ocean.  The water and the caught fish pull that net into a certain shape, and that shape can be manipulated by the boat, the current, and the fish (hello, Nemo!).  Another word for "net" is "mesh."  CAD programs also use the terms net and mesh to describe the wireframe drawings.

Finally, think of a Tiffany lamp.  A Tiffany lamp is like a three-dimensional stained glass window.  The lamp maker makes the wire frame first, and then fastens the glass pieces into the frame.  In 3D CAD, the glass pieces are called faces.

3D CAD is a little more complicated than Tiffanly lamps, though, because each face has an "in" side and an "out" side.  Designers have to make sure they get all faces facing (sorry) the right way.

Snooping around, and with a hint from the Internet, I found a couple of tantalizing command-line commands in DraftSight:  EXTRUDE and 3D.  They're definitely worth exploring.  Moreover, the main menu, under Draw --> Mesh, gives an entire list of 3D capabilities.

Conclusion:  Yes. DraftSight has it all in there - vertices, edges, faces, wireframes, meshes, nets - a 2D program with built-in 3D capability.  Now we just have to figure out how to use it all.

1 comment:

Oficina do Corten said...

Hello! Thanks for your experience in DS, i was catching my tail with this 3d stuff in DS, unfortunately my DS was in portuguese (its what we speak here in Brazil) what turned me crazy, now i changed the interface to English and can find the shortcuts and with your tips i´m starting...