What the..? with surfaces in Inventor

[2grumpy]

i am trying to find answers in Inv help and can not so i decided to ask you guys. Attached is an image from 'browser' - why so many the same surfaces - why each boundary patch is shown in 3 or 4 places why one Boundary patch stays represented as it was and the other get 'hold by hand' and another copy(?) or representation shown in browser?

And at last - question to Autodesk developers - why there is no sufficient information on above matters? or why it can not be find in simple way of typing the "Boundary Patch" and search?

[JDMather]

The Solid1 in the Solid Bodies folder is created from the Boundary Patches so logic says it has to be listed.
The Boundary Patches are surfaces, so logic says they have to be listed in the Surface Bodies Folder.

The hand means they are shared features.

While Delete Face is certainly a valid techinque in surface modeling - in my experience when I see a feature tree like this - it is almost always a convoluted method to getting the desired geometry.

Given your stated confusion - can you attach the file here for other to perhaps suggest other techniques?

[2grumpy]

Thanks for your input. I am working on customer file created in different software and trying to change design of the part. Sorry i can not send the file. i need to opposite hand parts and while i have no problem with creating one solid the other using the same technique does not solidify?

Could you please explain why one of the patch got the hand appearing and what it means?

[SBix26]

If you have one hand already modeled properly, then you don't need to model it again for the other hand! Use the Mirror tool, select mirror whole solid, and select the New Solid button.  Now you will have a multibody part with both hands, and you can do additional work on each one separately.  Any time you want to add a new common feature to both, just roll the EOP marker above the mirror feature and add it there.  Then, of course, you create individual parts from those solids (Make Components).

[JDMather]

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@2grumpy wrote:

Could you please explain why one of the patch got the hand appearing and what it means?

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I thought I already did.  The hand means the geometry shared by two (or more) features.

In addition to suggestion of modeling multi-body mirrored you could also start new part and Derive Component the mirrored part.

To bad you can't post the file - I would bet there is a significanlty easier way than whatever you are trying.

[mbenoy]

You also might want to take a look at the toggle "Auto-consume work features and surface features" under the "Part" tab in the Options.  You might find that you prefer it the other way.

[2grumpy]

yes but it is not so clear. i have attached example file to show my issues.

my question are why extending surface 15mm does mean 13.5 mm? why applying different order to stitch i have different result - surf 5 & 6 in part exa5 against 3 & 4 in part exa5a.

also do not understand why to work on surface we have two environments model and construction?

that for start - i still have many more questions. 

[JDMather]

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@2grumpy wrote:

...also do not understand why to work on surface we have two environments model and construction?

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Where are you seeing Construction Environment unless you are using imported data?

As I suspected this is going to be a mess - my initial opinion is that unless I am missing something you are going about this all wrong.

We'll see if we can work towards the solution. (I could be missing something.)

I am going to concentrate first on exa5a.ipt - this might take a while, so bear with me.

[JDMather]

I don't see the logic to Delete Face 2 or 3.

[2grumpy]

Attached file is example only - the real shape in file i am working is much more complicated and it make sense.

You can see in this very simple, basic shape and even it creates issues.

[JDMather]

Look at the buldges and dips in Boundary Patch3 - don't you intend for these to be two planar faces?

I look at that and see what I call "garbage".  (this offends some here - if I'm wrong, let me know it)

[JDMather]

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@2grumpy wrote:

Attached file is example only - the real shape in file i am working is much more complicated and it make sense.

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If your real part is much more complicated then we have much more work to do.  This simple part isn't looking too good.

[2grumpy]

look JDMather - i am trying to find answers to my problems - i can not find it in INV help - and it seems to: you trying to prove me wrong.

Good buy mate.

[JDMather]

Is something like this what you are after?
You didn't answer the question about whether you wanted planar faces at that boundary patch?

I warned up front that this will take some work to figure out the true design intent without the actual files.

If you give up this easily - you won't find the answer in the Help files.

[mbenoy]

I'm not sure of the reason behind it, but if you have multiple surfaces, you can get different behaviors depending on which ones you stitch and how.  I'll give it a shot to explain what I've experienced.

If you have multiple surfaces in your model, perform a stitch command and include some but not all, if the included surfaces are below the excluded surfaces in the tree, they will not be shared.

Conversely, if the included surfaces are above the excluded surfaces they will be shared.

In your example here, you have Boundary Patches 1, 2 & 3.  When you stitch 1 & 2, surface 3 is below and excluded so they share 1 & 2.  When you stitch 3 first, 1 & 2 are excluded but above and so 3 is not shared.

To test, move 1 & 2 below 3 in the history tree and then perform your two scenarios.

[JDMather]

Here is another possible solution.

[2grumpy]

Thanks Michael, i have the same experience - when working with surfaces you never can predict the outcome. Very bad Inventor behavior - i my opinion unacceptable for professional software. For that reason i am avoiding 'surfacing' as i cam but sometimes can not. And i have run in trouble this time again wasting time on reworking forward and back. 

[JDMather]

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@2grumpy wrote:

... when working with surfaces you never can predict the outcome. Very bad Inventor behavior - i my opinion unacceptable for professional software.

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Totally predicatable for me.

In fact, Michael explained the predictable behavior.

Based on the evidence you have posted so far - it looks like you could benefit from professional training.

Where are you located.

[mbenoy]

I would never agree with the idea of avoiding surfaces.  In fact, I don't think they are used enough.  I have witnessed how that can limit someone's design possibilities.

With all due respect, it looks like you're worried too much about how it shares or doesn't share a surface, or whether it's consumed or not.  How many times it's in the tree, if you will.  I'm not saying that the way it handles it makes sense, but then I've never really been bothered by it either.  But hey, if it bothers you - it bothers you.  I would say that I wish they would stick with one way or the other and not a "depends on the situation" type of thing.  Maybe that's the issue.

If you are planning to reuse surfaces several times then I might point back to my earlier suggestion of turning off the "Auto Consume" option.  I have used Rhino for years and I have a particular way I like to model.  I disable the auto-consume and prefer it that way.  Maybe give that a try and see if it works better for you.  It's a little harder to know what was used where but I've been doing it that way for years. 

[2grumpy]

Thanks for your input.

 i do not 'worry' abbot if is consumed or not but i do try to understand hot will happened if i do that or that - and this is important to have 'picture' what and how to work and that appears to have different results depending on order i work - strange to me. i am worry that when extending surface by "distance" or "measure" say 15mm it extends only 13.5mm. i came across that issue accidentally. After all we are using 'parametric' software.

i do share your point of view - i am trying to use 'surfaces' in my work and do see this method as valuable in some circumstances only 'surface' can produce outcome you wish for.