Extrude Problem

[Memnon]

Hey guys,

I'm rather new to inventor and I've been fiddling around with Inventor 2008 (Student version from Autodesk)

I got used to some of the easy problems in the book I have for the school I'm going to. Seemed pretty easy, just draw some simple stuff, extrude and bickity-bap, done!

However I came across this problem yesterday when i decided to try some extra problems. The center keyhole is hollow. The center circular area is supposed to be 4mm thick. The outer ring area is supposed to be 6mm thick. All the holes in the outer ring area are through. The undulating surface of the outer ring was created by using circles and center line arcs arrayed in circular patterns.

My problem is when I go to extrude, I can't seem to select anything other than the keyhole area or any of the holes in the outer ring, the very things that are supposed to be hollow. I suspect it may be a constraint problem (these are still a bit confusing to me and I did read Mathers PDF file). When I try to use "close loop" I get messages saying something to the effect of the object being over constrained.

What am I doing wrong?

[JD Mather]

I got used to some of the easy problems in the book I have for the school I'm going to. Seemed pretty easy, just draw some simple stuff, extrude and bickity-bap, done!

But I'll bet all wrong judging from your attached file.


(these are still a bit confusing to me and I did read Mathers PDF file). What am I doing wrong?

Go back and read again. The center of your part isn't even at the origin.

I would recommend patterning features rather than sketches. What book are you using (I've seen this same problem come up serveral times)?

Do an experiment: Edit the sketch and Right Mouse Button select Show all Constraints. This is a disaster. And your sketch isn't constrained.

[Memnon]

What book are you using (I've seen this same problem come up several times)?Engineering Design & Graphics with Autodesk Inventor 2008 *custom edition*


The center of your part isn't even at the origin.The book doesn't mention anything about an origin point. At least not up to the point where this problem sketch is. I double checked.


Edit the sketch and Right Mouse Button select Show all Constraints.Did that. There are a gazillion "constraint bubbles" all over the sketch. Looking closer at them the vast majority seem to be related to midpoints and patterns.

This is a disaster.LOL you ain't lyin'!

[MarkFlayler]

Oh man, yes that book is garbage without a good instructor. I have used it before (there is only one chapter for all the part modeling commands, what a joke). The problem with your first sketch; well there are lots as JD pointed out, but the main issue is you have an open loop in your profile. I also am guessing you go to ITT Tech? :wink:

Here is an extra document on using the Origin for your designs though. It is really important that you anchor and fully constrain your base sketch.

imaginit.rand.com/files/The%20BORN%20Technique.pdf

Regards,

[Memnon]

Thanks for the extra info MF. I know for certain now that nothing was taught about the origin in the first two chapters of that book (which is where we're at). I finally re-tracked down JD Mathers Becoming an Autodesk Inventor® Professor in 90 Minutes and going through that tutorial as well to help me re-do this sketch and have my future ones be less of a disaster.

See, this is why I always try to look for information outside of what I was given. I always seems to have to do this back when I was working too.

[JD Mather]

...going through that tutorial as well to help me re-do this sketch ...

It probably only has a sentence about using Pattern Features rather than Patter Sketch.

I seldom use Pattern Sketch.

Your sketch for this part should be shaped something like a piece of pie. Do your Extrudes, and then Pattern the Features.

I've got this one already done somewhere if you get stuck.

[Memnon]

I haven't forgotten about this thread or this problem. I've just been working on some other exercises including your cupcake pan. I'll post it when I'm done.