Design Intent

One of the biggest advantages Parametric Modellers carry over other forms of CAD is their ability to change and update models which have been created already with very little work.

For example: This tool’s size can be changed from this……….

…….To this…. …with very little effort.

DESIGN INTENT, is the plan of how we wish the part to behave when such changes are made. Let’s take an example….

The sketch shows a rectangle with two circles sketched onto it. Each hole has been dimensioned as being 30mm from each side

The resulting part can be created through extrusion

The length of the rectangle side can be changed from 150mm to 200mm. We can see that the captured design intent keeps each circle 30mm from each side.

The resulting solid, formed through extrusion

In this instance, the holes are dimensioned using a baseline as shown.

Again we see that changing the dimension of the rectangle has an effect on the location of the circles.

The new solid

Overall we can clearly see that differently captured design intents on the same Sketch can have very different effects on a part if changes are ever made.

To describe design intent in even more detail, we will take another example

A 3-D block is shown which has been formed by extruding a 2-D sketch into a 3-D solid. The height of the extrusion is 40mm and thus, the height of the block is 40mm.

A sketched circle has been drawn on the top surface of the 3-D block.

Using the extrude cut feature, the circular sketch has been extruded down into the solid to remove a cylindrical hole from it. The condition of the extrusion is set to "Blind" as default. This removes the desired shape from the solid and it is suitable for the moment

If it were decided that the height of the block needs to be increased from 40mm to 60mm, Solidworks can easily do this. However, the depth of the extrude cut remains at 40mm, leaving the step as shown.

The design intent in this case calls for the extrusion to be all the way through the solid block at all times. By selecting "Through all" in place of "Blind" when extruding the sketch, no matter how big or small the block is made, the extrusion will always be all the way through the block.

ALWAYS consider design intent BEFORE starting to draw.