Conversion of relative joint to absolute
This function is used to convert the relative joint to the absolute one. By this conversion, we get, for example, the option to change the joint position at will. Unlike the absolute joint, the relative joint is fixed to the reference member and can be positioned only along its axis. This tool is activated by the "Convert to absolute" option in the context menu of the joint. It is then possible to convert relative joints by clicking on them in the workspace. After clicking on the relative joint, a window appears where it is possible to choose whether or not to split the reference member.
If you select the option "Divide the reference member in the joint", the reference member is divided into two separate members that are connected to the joint.
If the option "Do not divide the reference member" is selected, the reference member remains intact and the joint is disconnected from it. The connection between the joint and the member is thus lost and the structure is then discontinuous at this point.
Window "Change of relative joint to an absolute one"
The potential of this function is shown in a simple example of a duo-pitched truss:
In the first case, the joints on the top chords of the truss are defined as relative. When the Z-coordinate of the apex is changed, the pitch of the connected top chords changes and so does the position of the relative joints on them. The truss is still duo-pitched.
Modification of the truss with relative joints
In the second example, the joints on the top chord were converted to the absolute ones, the reference members were split (option "Divide the reference member in the joint"). When the Z-coordinate of the apex is changed, the position of the joints on the top chords remains unchanged and a trapezoidal truss is created.
Truss with absolute joints and split reference members
The last case shows an option where the joints on the top chord are converted to absolute, but the option "Do not divide reference member" has been selected. After the apex modification, the pitch of the top chords is changed as in the first case, but the position of the converted joints remains unchanged. The webs are no longer connected to the top chords.
Structure with absolute joints not connected to the original reference members