While direct modeling software has been around for a while, I started paying close attention only when SpaceClaim came around. I am now convinced that this is the way ahead and whether the CAD vendors like it or not, their customers are going to ask to be served this dish. So they had better learn to cook it sooner than later.
For the benefit of those completely new to Solid Edge ST, I will first explain a few concepts. In my opinion, the main concepts that need to be understood are:
1) Steering Wheel – The direct editing tool that does all the magic
2) Live Rules – The rules that decide how this tool behaves
3) 3D Dimensions – Geometry driven by dimensions
4) Procedural Features – Arrays and patterns
The Steering Wheel
This contraption is responsible for all the direct editing in Solid Edge ST. It pops up when you click the mouse on a face. The big sphere at the center is called the origin knob and is positioned at the location where you clicked the mouse. The steering wheel can be moved to another face or even left dangling in space. To move the steering wheel simply click and drag the origin knob and the steering wheel moves along with it.
The long arrow is called the primary axis and automatically aligns itself to the face normal. In case of non-planar faces, it aligns with the normal at the location where you clicked the mouse. The primary axis points to a small sphere called the primary knob which can be dragged around to reorient it.
The small arrow is called the secondary axis and points towards one of the four secondary knobs on the steering wheel. To point the secondary axis to a different knob simply click the knob. There is also a blue disc between the origin knob and the wheel which is used to move geometry in its plane.
By now I guess most of you must be saying, “Enough of this axis and knob stuff. Tell me what this thing actually does?”. Well actually, the steering wheel does just two things: Move and Rotate. They call it the synchronous move and synchronous rotate. These two are fundamental to understanding how direct editing occurs in Solid Edge ST. You get this wrong and you will find yourself clicking and dragging stuff around and getting weird results. Given below are two very simple examples of a synchronous move and synchronous rotate.
In the first case, I moved the top face along the primary axis. In the second case I reoriented the steering wheel while keeping its origin on the top face, and then rotated it about the new primary axis. The top face got rotated as well.
Now reorienting the steering wheel can be a hassle. It involves setting the secondary axis correctly and then dragging the primary knob around. You can often skip this step. Simply find another face to attach the steering wheel to. In my case, I moved the steering wheel to the front face and then rotated it. The front face was not selected and hence did not get rotated. The top face was selected and got rotated instead. Exactly what I had in mind.
I have only scratched the surface of the steering wheel. There is a lot more that can be done. To give you an example, there is something known as “Solve Type”, which basically contols how adjacent faces on the model react to the modification. You can set it to simple or adaptive. In case of simple, adjacent faces are extended or trimmed as required, but will maintain their original orientation. In adaptive, adjacent faces are extended or trimmed as required, but can also change their orientation. The figure below shows the same face rotation operation with simple solve type on the left and adaptive on the right.
Simple and Adaptive Solve Types
I noticed that double clicking on the various parts of the steering wheel does not do anything. Actually the double click is processed as two single clicks, which means that the programmers have not processed the double click mouse event at all. Since reorienting the steering wheel can sometimes be a pain, it would be nice if double clicking the various parts of the steering wheel could do something intelligent and useful. For example, double clicking on a secondary knob (one of the four knobs on the wheel) could reorient the steering wheel to make the primary axis point in that direction. So in the case above where I reoriented the steering wheel manually by dragging the primary knob and waited patiently for it to snap somewhere, I could have simply double clicked on the required secondary knob and my steering wheel would have been already set up.
Similarly double clicking the origin knob could move the steering wheel to the centroid of the face or maybe someplace else. Double clicking the primary or secondary axis could swap them, and so on.
Next time I will discuss Live Rules. That’s when things will get really interesting.