How to extrude a "partial" annulus

[Anonymous]

Newbie.

I want to extrude an annulus, but one that has channel cut through it.  An annulus that does not go all the way through 360 deg.

I make a sketech, draw two circles, and then draw lines where I want to cut the annulus.  (The lines are parallel to each other, and parallel to an axis.  They are not radial lines.)  I constrain the endpoins of the lines to lie on the circles.  But back in 3D Model, I cannot extrude the partial annulus.  I can extrude only the full annulus.

I presume that Inventor does not recognize my "closed" loop.   Sketch Doctor finds no problems.   What do I need to do to get Inventor to extrude the partial annulus?

[mcgyvr]

post your ipt file...

You may have to use trim/extend to get a valid closed profile.. or use "select other" if you think what you have is valid

[Anonymous]

Here it is.   Since I posted, I extruded the entire annulus, and I'm trying to "extrude out" the channel.  That's what you'll see.

Generally,  am I better off just posting the .ipt file when I first ask a question, or should I wait until someone asks for it?

[mcgyvr · Accepted solution]

Always better to just include the part right from the start.. (and don't forget.. if attaching an iam file you must also include all ipt files as the iam just links to files and does not include them in itself)

You didn't have a valid closed profiles and extrude dialog shows a red + because of the open loops..

You didn't have coincident constraints on the end points of those lines to the projected circles.

You are missing dimensions,etc...

If you go to your constraint settings do you have "infer constraints" (and persist constraints) turned on?

[Anonymous]

Thanks, but I got it.

Ultimately, my constraints were not set properly.   I chose "show constraints" and I could see that they were not all there.   But I had a hard time figuringing out the correct sequence of clicks to make it right.  One possible problem was three similar, overlapping sketches.  I might have been seeing features on other sketches other than the one I wanted to edit ... I'm not sure about that.

At any rate, I'm ok for now.   Thanks as always.  

[Anonymous]

Thanks.  I'll have to look into your comments.  

I've been dropped into this with no training or preparation, so I'm learning as I go.

I don't seem to have that menu.  I should have mentioned that I'm using Inventor 2013.  I have a "Constraints Options" menu that has just the lower panel of what you posted.  I also don't remember any red + when extruding, but maybe I just didn't notice it.  No need to respond, unless you want to.  But my feature is ok now.   Thanks again.

[mcgyvr]

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@Anonymous wrote:

Thanks.  I'll have to look into your comments.  

I've been dropped into this with no training or preparation, so I'm learning as I go.

I don't seem to have that menu.  I should have mentioned that I'm using Inventor 2013.  I have a "Constraints Options" menu that has just the lower panel of what you posted.  I also don't remember any red + when extruding, but maybe I just didn't notice it.  No need to respond, unless you want to.  But my feature is ok now.   Thanks again.

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Another tip.. Either put your Inventor version (and computer specs) in your signature file (like mine) or state Inventor version at the start too..

And yes.. the menus have changed.. You want to turn on "constraint inferrence" and "constraint persitance".. You should see those buttons around the constraint area..

I thought they were more visible in 2013 so you should be able to find them..

[JDMather]

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@Anonymous wrote:

I've been dropped into this with no training or preparation, so I'm learning as I go......

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I recommend that you spend a bit of time going through these.

The interface has changed a bit - but the basics are the same.

http://forums.autodesk.com/t5/inventor-general-discussion/skillsusa-document-now-on-screencast/m-p/5856691#M564801