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1-Visitor
February 19, 2015
Question

lack of precision in Creo Elements / Direct Modeling Express?

  • February 19, 2015
  • 2 replies
  • 8409 views

Hi Folks,

 

I am using Creo Elements / Direct Modeling Express. I like it a lot in some ways. But I find that I am spending quite a bit of time repeatedly fixing things that seem out of place or not quite in the right position. Parts that I thought I had snapped properly into place when I later look closely are not really in the right place. Parts that I thought had been put in place with faces at right angles to other parts, turn out later, when I look closely, to not really be at right angles. I will sometimes use the "mate" and/or "align" functions to make the corrections. That works but I am spending much time correcting these types of things. I used to use AutoCAD and I don't remember this problem with that program (or at least it was less common, to the best of my recollection). Do other users see this problem with Creo Elements / Direct Modeling Express? Is there anything that can be done about this?


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2 replies

17-Peridot
February 19, 2015

Hi Vincent,

I can not confirm these inaccuracies as you describe

If the result of the work is not right, I caused it myself

But a source for inaccuracies can be be the measuring.

By default is measured with an accuracy of six decimal places.

This can be to inaccurate, if you are using the measured values for movement or modeling.

Try this.

File Settings System Measure and switch Distance and Angle from 6 in all.

One more question.

How big are your models? It is advised to go not greater than a sphere of radius 100 meters.

You can go bigger, but then inaccuracies may be caused

1-Visitor
February 19, 2015

Hi Friedhelm,

Thank you for your response. I just adjusted those things. (I went to File->Settings->System->Measure -- right?) The settings for distance and angle were 6 and 1, respectively (I think that represents the number of decimal places shown). I changed both to "all." But I think that this will not affect the accuracy of the snap system. I almost always use the snap function to position things because that should be the most accurate. I only rarely move things by entering a displacement value (well sometimes I do that but usually only when I know the exact amount of the displacement and it is a simple number, like 1/16 of an inch [0.0625] or 1/32 of an inch [0.03125] or 90 degrees). So I think that changing this setting probably will not fix the problem.

17-Peridot
February 20, 2015

Hi Vincent,

So I think that changing this setting probably will not fix the problem.

I think so too.

But it is almost impossible without more information to see where it comes to your problem.

If you would upload an example, we could try to check it out.

Maybe two .pkg

One before, one after the misalignment

Another question.

Do you use maybe imported parts?

1-Visitor
February 20, 2015

I have seen users have issues similar to what you have described; usually the reason has to do with not being careful with catching, snapping, and selection. Just because the cursor is over a particular point, vertex, edge, or face when you click with the left mouse button, it doesn't always mean that it will catch to that point, snap to or select that vertex, edge, or face. The software will almost always highlight points, vertices, edges, and faces if they are being caught, snapped to, or selected; so watch for that as you are modeling.

Usually I hear the opposite problem with Creo Elements/Direct Modeling-it is too precise! I will seen lots of parts that are designed in other CAD software (as solids) that cannot be imported into Creo Elements/Direct Modeling as solids because the model was not modeled precisely enough for Creo Elements/Direct Modeling. Some software can assume that two faces are connected even though there is a gap of 0.1mm, but Creo Elements/Direct Modeling requires gaps to be at most 0.01mm.

1-Visitor
February 21, 2015

Hi Peter,

Thank you for your comment/post. It is possible that you are correct about what has been happening (although I am not certain). Maybe I just have not been being careful enough in snapping to objects and points. I will try to pay attention to that and see if that is the problem.

Thanks,

Vincent