Keeping sketches simple in Inventor

By Shaun Griffiths

In order to create geometry within inventor you often need a sketch. With this, you may be tempted to use previously understood AutoCAD methods for generating geometry with lots of construction lines, trimming and extending. However, with the parametric nature of inventor it is often easier and less prone to generate problems if you create simpler sketches that are heavily reliant on constraints, fewer lines and commands.

To create a profile such as the one above, you may be tempted to create arcs and circles and then trim down relative lines. However, here I will use a workflow of creating a simple controlled profile by drawing what you see, or intend, with one line. Followed by applying relevant constraints and dimensions. To begin with you can draw a simple line, which allows you to continue drawing straight lines when the end point is highlighted yellow.

However, to draw an arc, if you hover over the end of the line, the endpoint will become grey.

At this point, you can click, hold and draw the radius of the arc in the direction you wish, by moving the curser directly from the endpoint and around as if you were drawing the arc with a pencil.

From here, you can utilise the generated snap lines to keep your geometry lined up to suit your sketch design intent.

If you stop holding the left mouse down, the arc command will finish and allow you to continue applying straight lines.

Now, by repeating the same method, you can complete the below geometry with one line.

Next, you can apply the relevant constraints to maintain the shape and follow the rules of your design intent. For example, some of the constraint may have been applied automatically, such as vertical, perpendicular or tangency constraints, but you may need to add more. For example, in this case, I want to add some equal constraints to keep the shape symmetrical. Then, instead of drawing construction lines to further complicate the profile, I can use the vertical and horizontal constraints to line up the centre points of the arcs to the origin of the sketch.

Now you can dimension your profile to fully constrain it, thus providing a simple sketch profile that is easier to control and maintain.