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Why do features affect surfaced faces?

Pioneer
Pioneer

Hello.

 

 

Why does the surface face I created change geometry when I add an edge blend to my model and how do I prevent it from happening?

 

I'm modeling vanes for an impeller. I created the vanes by using surfaces. Once I have the vanes how I want them, I want to add an edge blend so it "attached" to the hub plate of the impeller. As soon as I add the edge blend between the vanes and the hub plate, the geometry changes. Causing my vanes to be out of the tolerance field.

 

 

7 REPLIES

Re: Why do features affect surfaced faces?

Siemens Creator Siemens Creator
Siemens Creator

Any chance you can include some images or a simple part?  From your description, the blend should not be impacting the original surface so I'm wandering if there is some dependency you've created

 

Keith

Re: Why do features affect surfaced faces?

Pioneer
Pioneer

Hi,

 

 

you might be right about the dependency. I'm still learning how to surface model. 

 

Here are the images. the blue areas are a facet body I'm using as an underlay. Which I use as an indication of the geometry changing.

 

2018-02-21 12_00_36-NX 11 - Modeling - [Test impeller (3D C1 STG4).prt (Modified) ].jpg2018-02-21 12_01_00-NX 11 - Modeling - [Test impeller (3D C1 STG4).prt (Modified) ].jpg

Re: Why do features affect surfaced faces?

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

If you perform a deviation gauge before the blend and after the blend.

Are there big changes between the 2 results?


Ruud van den Brand
Pre-sales NX CAD
cards PLM Solutions

Re: Why do features affect surfaced faces?

Pioneer
Pioneer

The error sections shows an increased amount in out of tolerance numbers. (+15-20%)

 

 

I must add to this topic that the facet body I'm using as an underlay is actually a step file that i converted to an STL file. I'm using this purely as a training basis as laser scanned objects most likely already have out of tolerance deviations by erosion or other factors.

Re: Why do features affect surfaced faces?

Siemens Creator Siemens Creator
Siemens Creator

Since you are doing the deviation checking to a facet model, then you may find that the sampling points are changing location and therefore reporting different numbers... best way to check if the blend is changing you actual surface would be to extract the surface before the blend (at Timestamp) and then check between the two surfaces (before and after blend)

 

Keith

Re: Why do features affect surfaced faces?

Pioneer
Pioneer

Hello.

 

 

I'm not sure if I'm doing it right what you're saying. I extracted the surface as you said and checked before and after blend.

 

Before the blend I will get 544 samples and 4.6% out of tolerance

After the blend I get 403 samples and 17.2% out of tolerance.

 

Is this what you mean? 

Re: Why do features affect surfaced faces?

Phenom
Phenom

Ciao @MKarsten,

 

you have to compare the exctracted and its blended original.

 

Ciao