why is a revolved shape's flat face not recognized as plane?

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Top'Noob
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why is a revolved shape's flat face not recognized as plane?

Unread post by Top'Noob »

I have had minor difficulty with this issue on several occasions.

It seems that a revolved shape cannot be recognized as a "plane" even if the entire face is completely flat.

There is always a way to work around it but this can be a little aggravating.

Can TS be improved to recognize any flat face as a plane ?

For example, I have attached a parasolid with 8 holes in one face. The bottom of the holes is flat when checked with "analyze curvature" but this face cannot be selected as a plane. It returns the error "invalid plane".

Some sort of official response to this inquiry would be appreciated. 8)
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PK
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Unread post by PK »

Hi Top'Noob

It looks like the bottom of the holes are not totally flat.
If you put your digits number on 12 and use Analyze | Curvature you
will get the following result:

Minimun radius of concavity=0.000000000194mm, Minimun radius of convexity=0.0mm

Regards

PK
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Unread post by Top'Noob »

Thanks for the explanation.

In inch mode I get Minimun radius of concavity=0.000000000008in

Should there be some point where the software realizes that the value is insignificant and just calls it flat ?

Or perhaps if an entity is truly flat the system could return "FLAT" instead of "Minimun radius of concavity=0.0in, Minimun radius of convexity=0.0in" when using Analyze Curvature.

This would make it easier to notice whether the "digits number" is concealing some miniscule value...
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jehronimo
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Unread post by jehronimo »

Hi,

I am not sure to understand your problem :?

I tried with your part, designed a pink body trimmed by a plane, and the plane is the upper face of your green shape...

With 15 digits, if I check the volume of your face, there is no deviation on Z axis...Also with this 15 digits, the result of the Curvature analysis is 0mm...

Maybe I miss something :roll: :D

Jehronimo
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Top'Noob
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Unread post by Top'Noob »

Hi Jehronimo,

We are talking about the flat face at the bottom of the holes. It looks like you are checking the large flat face. :?
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jehronimo
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Unread post by jehronimo »

Hi,


:shock: I read your post too fast, what a pity!! But I am wrong also because...if I check the holes bottom face, the system says that those faces are conical faces!! So I am not sure, one more time, to check the correct face :?

:?: :?:

Jehronimo
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Unread post by Top'Noob »

You are doing the same as me now 8)

I also get a cone (very slight angle).

I must have made a mistake when I created the curves to revolve.

Thanks for the help !
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Bill
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Unread post by Bill »

Hi,

While I understand your problem, (with the revolved surfaces), why are you doing a revolved shape on this model for these features? Why not use a simple drilling or a pocket? These are more direct ways of creating the features you are showing in your sample...(without all the hard work).
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Bill
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Unread post by Top'Noob »

Hi Bill,

Well now we'll have to move this to OFF TOPIC ! (joking)

You are correct that there are easier ways to create this. There is, however, a method to my madness.

This is an electrode. I originally used "subtract" to get the geometry onto the electrode block and then removed and modified some faces to create some clearance in certain areas. This left me with an electrode that is exactly the same as "steel size". I sometimes machine electrodes in this condition and lie about the cutter diameter or specify negative stock to leave (depending upon the nature of the feature to be burned). In this case I decided that the best course of action would be to offset the electrode geometry and machine to that offset geometry to achieve spark gap.

Creating a planar section and from that a contour to offset and revolve seemed to be a good way to do it.

Here is the "madness" I spoke of...
I try to avoid manually creating geometry because :

1. I am lazy :oops:
2. There is more chance for errors in my opinion
3. 90% of the shapes I work with are too complex to reproduce manually

So I think you are saying I could have simply made a pocket with tapered walls and added the radius and been done with it. You are correct but this is just not how I am used to working. Maybe there is room for improvement here...

In this particular case I will have to agree that it would have been better to measure and create features "from scratch".
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Bill
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Unread post by Bill »

I understand why you are working this way then. My question would be why are you not useing TopSolid'Electrode to create such a detail with? TopSolid'Electrode can create this detail lightning fast, and automatically for you...I have included an image of a simple rib trode. This trode is created automatically by the software with a true square orbit. (sorry, this one is a new feature of 2008) :-)

But now you have something to look forward to!
[/img]
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Bill
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Unread post by Top'Noob »

All right...

I promise... SOON after getting my hands on TS2008 I will play with Electrode in demo mode.

Any chance I can get a tutorial with that ? 8)
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Bill
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Unread post by Bill »

Sorry, today, I do not know of one. I will teaching our users this new function during our TopSolid End User Conference this month. (we are doing a 2 day update training session with our users).
Happy Designing
Bill
Technical Director
Missler Software Inc
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