|Visualizing Small Model Changes
Often when working on a model, especially a complex shape, it is hard to see the effects of changes to driving geometry.
In Figure 1, there is a surface driven by several features including solid geometry, curves and other surfaces.
The task is to adjust the surface to better meet some goal -- perhaps clearance, look, or in this case shape.
As a designer you need to change driving geometry to create the effect, but it's hard to tell just what moved and
how much when you make changes. To "see" the changes you simply need to create some static geometry to compare.
One method is to save a copy of the model, then assemble the 2 together in a comparative assembly so you can easily
see the differences. See Figure 2. IGES geometry can also be very helpful.
Another method for local changes is to create a curve (or three) through the area of interest. Do this by making
a new datum crossing the area, then create a curve through the intersecting surfaces. Insert > Datum
> Curve... > Intr. Surfs > ... (See Help for more info.) This will give you a curve through
the area that will always follow the current geometry.
Next, Sketch a datum curve on the same plane used for the surface intersection curve. Insert > Datum >
Curve... > Sketch > ... Do this by selecting 2 references that will not change (perhaps default
datums), then use the curve you just created (Sketch > Edge > Use...). (For info on the
selection filters see Help.) Once you have selected the surface intersection curve, it will become a reference.
Open the references dialog box and delete all references to the curve. (Keep your non-changing references.)
Sketcher should auto dimension the curves.
Be done with the sketch and complete the curve. You will then have two curves exactly identical, but not
related. You can check that the curve is not related using Info > Feature then look at the
parents. The surface intersection curve should not be a parent.
Now you can modify the area of concern and following regeneration, you will see the surface intersection curve at the
new contour, and the sketched curve at the old location. In this way it is easy to see what, and how much things
have changed. See Figure 3.
When you are done with the changes and satisfied with the work, just delete the plane and the 2 curves.
Tip: If you use multiple curves as in the pictured example, Figure 3,
you can change the colors using Modify > Line Style for easier visualization.
Have a Great Month!