Rotating an object in 3D space within Onshape is easy. Just hold the right mouse button and drag. You probably do this dozens (if not hundreds) of times a day. I can’t imagine I’ve shared anything new with you so far.

But notice as I rotate, the model seems to flip and turn all over the screen. My point of view is being held still, and the model is being rotated “in front of me.” In many scenarios of my day-to-day modeling, this is fine. I just want to flip the object over to add another feature, or insert and mate another part in place.

However, if you look at my model of an engine desktop toy, you probably notice that it very clearly has a base. In real life, this object would be sitting on a table. What if I wanted to rotate the model, but want it to behave as if it were sitting on the table?

In Onshape, you can achieve this behavior, a rotation that keeps the vertical axis upright, by holding the ALT key (“Option” key for Mac) while dragging with the right mouse button.

In other CAD systems, this is called a “constrained orbiting” or “rotation about scene floor.” Your regular rotation behaves as though you (the camera) are standing still, and the object rotates freely around each axis in front of the lens. In contrast, “Alt + Rotate” behaves like the camera is on a boom and “flying around” to get a different angle, while the object itself stays stationary.

The difference might seem subtle, but this rotation method can be very handy to quickly get the right orientation without a confusing or disorienting flip occurring. Imagine that you are designing the automated assembly machine shown below:

This machine will be mounted to the ground, so it’s probably easier to understand WHERE on the machine you are working if it rotates as if it were sitting on the ground, right? Here’s a quick side-by-side comparison:

2020-07-14 - Tech Tip - How to Keep the Vertical Axis Upright Upon Rotation-Jul-14-2020-03-06-41-17-PM

We hope this little rotation tip changes the way you look at your models in Onshape!

Interested in learning more Onshape Tech Tips? You can review the most recent technical blogs here.