# We develop a belt drive in nanoCAD 21 (part 2 of 3)

## Modeling holes in plate elements with parameterization of dimensions

Creating holes in a sheet body (Figure 13) is no different from creating holes in regular bodies, but let me show you how this is done again. First, let’s draw a preliminary sketch of the hole.

Click the Add Sketch button and specify the inner face of the plate (Fig. 14).

Next, we build two circles and connect them with segments tangentially or with reference to quadrants. Additionally, we build segments connecting the centers of the circles and the center of the part (Fig. 15).

The next step is to auto-add constraints to all the rendered elements, including the crosshair of the center of the part. At this point, the sketch is automatically vertically aligned with the center of the plate. If this does not happen, you will need to impose an additional horizontal constraint on the segment from the center of the small circle to the center of the part. Add missing geometric constraints if necessary. I was not able to snap the line segments tangentially to both circles at once, so I add the Tangency dependence between the small circle and the line segments (Fig. 16).

The hole in the plate is made in one sketch. This means that it is necessary to form a single space by removing unnecessary lines and segments inside our sketch, which will lead to the reset of some of the constraints. Reselect the resulting elements and repeat the autodependency mapping (Fig. 17).

Add parametric dimensions: the radius of the circles and the distance between the centers. The last thing to do is to properly tie the hole to the plate. We add one horizontal dimension, and we already have a vertical anchor (Fig. 18).

We select the Hole command, indicate the sketch, and the program builds the hole (Fig. 19).

The remaining holes are cut in the same way. As a result, we get the finished part (Fig. 20).

To be continued…

Sergey Stromkov
engineer of the first category
ArkSoft company
arcsoft.ru