Inventor – Loft Angle and Weight

Lofting….I don’t know about you, but this has been one of the things I learned to hate.  Maybe because the application seems to have more control that I do during the process, or because I had some bad experiences with 3DS 10 years ago (pre MAX).  Whatever the reason, I just never liked Lofts very much.

Lofting is an extremely useful tool.  While you can reproduce the model by other means, the pain involved would be extensive.  The Loft Feature has so much control over the process, by weighted interpolation, there is no reason not to use it.  The trick is to control the interpolation to accomplish your goal.

Today, we’ll use Angles and Weights to create a transition between 2 other features, that would normally take a bit more time and planning to complete.

In the image below, you should see the part I needed to tie into another loft feature, with a specific angle at the transition.

While a Sweep around an extruded Feature might normally get a similar job done as easily, you would need more than 1 rail, adding complexity to process.  The Right side view (below) shows the problem with fillets and sweeps.  The rear edge is offset farther than the front, and the upper edge is not a typical fillet This is a perfect candidate for a Loft.

Inventor – Match Shape and Open Profiles

The Match Shape, and conversely the Match Contour option is available in the Extrude and Revolve Features.  These are not rocket science options, but do occasionally present confusion, either by the situation they are used with, or by the Inventor help available.

When an Extrude feature is created, it expects a closed loop profile, from which it will add a feature perpendicular to the plane the profile lies on.  Alternately, an open profile can be selected.

In the image below you should notice a small tray with a sketch containing an open profile dimensioned 20mm x 20mm.  The sketch was created on the face of the tray bottom.

Open Profiles

Notice in the image, the purple 2D sketch geometry that was referenced from the existing part geometry, and projected automatically when we selected the part face for the sketch plane.  This comprises a closed loop profile.  What will happen when we try and select the open profile in the corner?  This…

Inventor – 3D Intersection Curve

We recently reviewed Garin Gardener’s 3D sketching post, and highlighted the 2D and 3D sketching.  There was 1 point remaining that we didn’t have time to get to:

3D Intersection Curve

3D Intersection Curve is a feature that intersects in 3 dimensional space, the projected geometry from 2D sketches on intersecting planes (did that make any sense?)

Here we have a 2D sketch as well as a work plane created for the second sketch.

 

We need a new 2D sketch on the work plane. Don’t forget to project the geometry needed to work from (I used the endpoint of the line in the first sketch.  See below)

Inventor – 3D Sketch tips

This post has been moved over to http://johnevansdesign.net/2009/02/09/inventor-3d-sketch-tips/