Sketches

Sketches

Sketches, located under the Create menu, are constrained drawings on a 2D plane or surface, and the first step to any CAD model. To start a sketch, you click the Create Sketch button. Afterward, select a FLAT plane (could be your origin planes, planes you created, or a face of a body). Once within a sketch, you have access to sketching tools, which differ from normal tools.

Remember to use Construction Lines to define objects without splitting faces in your sketches. To make a line a Construction Line (invisible, dotted line) click the line and then click the X key.

Normal vs. Construction Line

Normal Line splits selectable area.

Construction Line maintains un-interrupted selectability.

Constraints

When making your sketches, make sure your lines are all black (this means that they are fully constrained). If the lines are blue that means the lines have some permissible range of motion, which you can see by clicking and dragging the line (note, sometimes the line or curve will not move because it is constrained in such a way that it has two unique positions; in other words, maybe it doesn't slide but it can be mirrored). If the line isn't fully constrained it may move in an unpredictable way when dimensions are changed. There are many ways to prevent this, and often times you'll need more than just one of the following tools:

You should NOT rely on the Horizontal/Vertical constraint because this defines itself based upon the arbitrary orientation of the sketch. In other words, if you constrain a rectangle's sides as horizontal and vertical, you will never be able to rotate it in the future. If you would define the right angles instead, you could rotate the rectangle based upon an angular dimension you define.

Dimensions

The most crucial part of sketches is dimensions. Dimensions are used to constrain sketch objects based on length, angle, etc. To open the dimension tool, the easiest thing to do is click the D key. Then, click whatever you want to dimension.

• For the length of the line, click the line.

• For the angle between lines, click the first line and then the second line.

• For the distance between points, click the first point and then click the second point.

You can enter parameters into dimensions.

You can click on a dimension to link two dimensions to each other.

Instead of just defining the length of the line (or distance between two points), you can define the distance in a single or multiple dimensions. To do this, move your mouse to the side instead of directly away from the line, as pictured.

Remember to ensure you define the correct dimension in your drawing, for example, radius vs diameter.