Trouble creating sketchs with curves that behave normaly later

[Anonymous]

I have multiple times in the past made sketches that have a portion of the sketch drawn as curves that are linked at their edges or one curve leaving another tangentially. These sketches do not tend to behave normally. After the sketch is done and if i want to extrude or revolve the sketch, any area that involves the curve won't select. I have been good about constraining and dimensioning the model during the drawing process. In some cases i have worked around this problem by using 'close loop' in the right context menu with varying success. What am i doing wrong?

[Anonymous]

Version? IV2009 has options to temporarily disable sketch
constraints. Check out Inventor 2009 New Features workshop under the Help
pulldown.

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[harco]

If you pattern in the sketch you are more likely to have problems.
Better to use feature patterns, they are more stable and you don't have the sketch contraint issues. Edited by: harco on Oct 21, 2008 11:53 AM

[Anonymous]

I using IV 2009

Jason

[Anonymous]

I not certain what you mean 'pattern the sketch' or 'feature patterns'

Jason
dell490
quadro 1400 card
4 gigs ram

[JDMather]

You have a huge number of repeated entities in you sketch. Edit the sketch and right mouse button select Show All Constraints. Inventor must solve all of those sketch constraints. It would be better to create one of those ribs as a feature and then pattern a feature. The result would be about half a dozen constrants rather than all of those you see following the instructions above.

[Anonymous]

OK,
I have deleted the pattern down to one groove,but i find one way to make a 2D element a feature and i don't see how i will make this 3D and then use it as a pattern to revolve or sweep around a round or non-round guide. I have attached a concept drawing done in SketchUp to illustrate the goal. i tried to creat a feature in 3D space but that seems to lead back to creation in the 2D world.

Jason

[JDMather]

>i don't see how i will make this 3D and then use it as a pattern

Have you read this paper?
http://home.pct.edu/~jmather/AU2007/MA105-1L%20Mather.pdf

[JDMather]

>I using IV 2009 Jason

The file says you are using Inventor 2008 not 2009, so I wasted time creating a solution you can't open. I didn't use your Sketch1 other than for reference as it was too complicated. Simple rectangular feature patttern of revolve rather than sketch pattern.

[Anonymous]

I am very sorry about the type saying 2009 . I have never used 2009 when i was trying to reply the site was not letting me log in due to some java error and when it did let me reply i must have typed too fast. Very sorry. I do really appreciate your help and reading the help that you give others.

I am going to read through the 90 minute PDF tonight after work.

Jason Taylor
AI 2008

[JDMather]

> I have never used 2009

The proceedure is the same in r2008. If you download the free Inventor LT http://labs.autodesk.com I can attach the r2009 solution that you can study.

[harco]

Edit your sketch.
Delete the sketch pattern that makes all the ribs.
Close the loop in the sketch making your jar unribbed but keeping the lines that make the rib cut.
finish sketch.
Create revolution of all the areas.
Make sketch visible and make one rib, a cut revolution from the rib cut lines.
Use the edge/line that you used to make the 2D sketch pattern direction to make your 3D feature pattern direction.
Sometimes its difficult to pick the feature but you can select it in the browser.
I would send you a model but the newsgroup keeps giving an error.

[dan_inv09]

The reason you have trouble with using a sketch with a pattern to make a feature is because the pattern constrains as a pattern and not to the other instances of the pattern, the curve you drew is not connected to the patterned version of it. And if you try to constrain the ends to each other you will get an error because they are already constrained in place. (When I thought I had to do the pattern in the sketch I found some success closing the loop by placing a point on one of the curves and then constraining that to the other one (adding extra constraints and entities and overall complexity).)

Nothing personal JD.

[JDMather]

>The reason you have trouble

Huh? I have no trouble with patterns. Pattern Features when appropriate. Pattern Sketches when appropriate.

[dan_inv09]

Sorry, the reason the OP was having trouble.

You, JD, like to tell how to do it the right way without ever explaining why the other way was doing what it was doing. Sometimes it has to be done a certain way and it would help to know how to get it to work.

[JDMather]

I thought Show All Constraints was self explanatory when it filled up the screen. I guess it just takes some trial and error experience to really understand the "why". Another good indication I have found is file size. The technique that results in the smallest file size is usually the most robust.

[Anonymous]

I did as you said and made a the revolve with out the rib detail. Then I made a new sketch with the rib detail and did a sub traction revolve with it and that made it easy to select the feature. It patterned well.

I took this original sketch and put it in a new sketch and trimmed it to utilize just the inner surface to make a fill for this jar but there is a problem with the interface of the fill and the jar and during rendering i get what looks like a polygon misfit at the intersection between the two parts made from a common mid-line.

Should this fill be made by derived part?

Jason Taylor

[JDMather]

You don't need a derived part. This problem is very simple. Post what you have at this point.

[Anonymous]

I tried to post it but the tread kept fail to attach the zip. I'll try again.
Jason

nope still failed. Zipped is still ok correct?

Jason

[Anonymous]

repost Edited by: jasonptaylor on Oct 30, 2008 10:49 PM