How to Reduce the Number of Edges for an Imported Surface?

Article by Alin Vargatu, CSWE updated March 23, 2012

How many times have you imported a neutral format file (STEP, Parasolid, IGES) in SolidWorks and encountered challenges when working on it?
Let me give you an example regarding edges: “How many open edges does the surface from fig. 1 have?”

Fig. 1 - How many edges can you count?

Did you say 1? Did you say 10? Actually the question was unfair, because you cannot count them just by looking at the model.
Let’s select them as input for a feature. All SolidWorks users that are Mold designers know that the Ruled Surface is a very important feature for creating manual parting surfaces, so let’s use it in this example (see fig. 2).

Fig. 2 - The Ruled Surface will have 40 faces as a result of the 40 original edges

Zooming in on a portion of the new ruled surface, we can see a poor result – just too many small faces (fig.3):

Fig. 3 - Too many tiny faces

These many faces are the result of the same number of small edges in the original surface. Fortunately, SolidWorks has a very elegant solution for this problem. Let’s Heal these Edges.
Roll back the feature tree before the creation of the Ruled Surface and apply the “Heal Edges” feature (Insert menu/Faces/Heal Edges) on the edges of the original surface (fig. 4).

Fig. 4 - Heal Edges


As you can see in fig. 4, I asked SolidWorks to merge all edges smaller than 0.1″ with an angular deviation from their neighbours smaller than 1 degree. The result is a reduction in number of edges of more than 50%.

Let’s see what we get when we apply the ruled surface this time (fig. 5):

Fig. 5 - Only 11 Edges - nice improvement

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Alin Vargatu, CSWE

Alin is a SOLIDWORKS Elite Applications Engineer and an avid contributor to the SOLIDWORKS Community. Alin has presented multiple times at SOLIDWORKS World, Technical Summits, and User Group Meetings, while being very active on the SOLIDWORKS Forum.