User Guide

RISA-3D User’s Guide
Version 5.0
70
Model Merge
Click on the Model Merge button on the Drawing Toolbar in the model
view to see this dialog:
In a nutshell, model merge looks for duplicate nodes and members (with the same
coordinates) and merges them into one. If the “Merge crossing members?”
option is checked in the model merge panel, RISA-3D will look for members
crossing each other, and connect them. A typical case might be X-bracing.
You have the option of merging the entire model or only a selected part of the
model.
Click on Apply and you will be presented with the results of the merge. Click Ok
to close the results.
Scaling Elements
Wait, what’s that coming in on the FAX machine?! The client has just submitted a
change order! He wants to raise the wood truss from 18'-6" to 22'-9", and he
wants the frame 25% wider (from 21' to 26'-3"). And he wants the completed
design this afternoon!
These are significant changes to the model. If you were using a program that’s
batch input or heavily reliant on “parametric” data generators, at this point you
would probably start the data entry process over from scratch to create the new
model. Remember that the true test of a program is how easy it is to modify
existing data because that is what you’re going to be doing most of the time.
A major strength of RISA-3D is the ability to make changes to existing data. We
could make the above changes entirely with graphic editing or entirely within the
spreadsheets. We will make our changes graphically so that we may use a few
more of these features. We will then explain how the changes could have been
accomplished within the spreadsheets.
First we will widen the truss and to do this we will use the Scale feature.
Click on the Modify menu and select Scale. (There is a Scale button on the
toolbar but we have ignored the menus up until now so it is time to use them.)
Looking at the scaling options the scale origin is the point that will remain
stationary as the selected items are scaled. We will leave these fields set to “0”.
The fields on the right are for the scale factors in each of the global directions.
We only need to scale the model in the global X direction to widen the truss.