Working with the X-Ray Tool


Dr. Frame2D provides various mechanisms for investigating the state of a structure or portions of a structure under load. The X-ray Glasses Tool () is the most general of these mechanisms, allowing one to isolate any arbitrary chunk of a structure as a free body, and to view the associated internal forces and moments. Other isolation mechanisms are described here also, along with some general tips for working with isolated views.

Using the X-ray Glasses Tool is straightforward:

  • To isolate arbitrary portions of a structure, click and drag with the tool to enclose the desired piece of the structure:
  • To turn off the isolation, choose Turn off X-Ray from the View menu, or reselect the X-ray tool if necessary, and then click somewhere outside the structure without dragging (i.e., create an empty isolation region).
  • To move a given isolation region without changing its size, hold down the control key while clicking on an existing isolation ellipse, and then relocate the ellipse as desired by dragging.
  • To quickly isolate a particular element, click on that element (hitting the "=" key will zoom in on the element in question after isolation) Note that the moment or shear diagram will be drawn as well, and the maximum values labeled automatically:
  • To quickly isolate a joint, click on the desired joint (in this case Dr. Frame2D will automatically zoom in on the joint in question):

With a joint isolated, you can increase or decrease the radius of the isolation circle by means of the Joint Isolation Radius Control in the tool bar:

  • Substructures can be isolated by clicking with the X-ray Tool on one member that has been grouped with others (Note: selected members can be grouped via the Group command in the Edit menu.):

Loads, supports, etc., can still be manipulated in the usual way even while the x-ray tool has created an isolation area.

Other Isolation Mechanisms

In addition to creating manual isolations, Dr. Frame2D can automatically isolate all members or joints simultaneously. The commands Isolate Joints (ctrl/cmd-J) and Isolate Members (ctrl/cmd-M) are found under the Modeling menu. This is an example of what the Isolate Joints command produces:

Similarly, the Isolate Members command leads to a depiction of each member in isolation:

Note that in the case of member isolation, the background grid disappears. This is because the grid does not have meaning once the structure is exploded.

 

It is also worth noting that again, the structure remains "live" while isolated--all the various loading and support manipulations are still available for use.

Tips and Notes:

The figures in the previous section make it clear that isolation views can get very busy. There are several things one can do to make the figures easier to parse:

  • Use the various scaling controls in the Scaling Toolbar to zoom in on areas of interest, to expand label spacing, force and moment depictions, and so on:
  • Select members and use the Decrease/Increase Label Offset buttons to move individual labels.
  • Use the hide and show options for force and moment labels. The figure below shows the same configuration as in the previous section, except with Moment labels hidden. While still busy, it is now much easier to read the force values.

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