topic Re: Self-intersecting loop in Inventor Forum

Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 10:41:53 GMT

I have fixed the problem but I usually get this type of error window. I couldn’t understand the meaning of this. What does this mean?

Re: Self-intersecting loop

mdavis22569 — Thu, 20 Oct 2016 10:49:13 GMT

fiatnm wrote:

I have fixed the problem but I usually get this type of error window. I couldn’t understand the meaning of this. What does this mean?

Use the sketch doctor fully click next or diagnose ... zoom in on your connection points (where the lines come together to each other.) One is overlapping more than likely

attach the part ...

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 10:58:07 GMT

One is overlapping more than likely
---------------------------------------------------------

Could you please explain this in detail?

After seeing green dot only point is selected how can it be go wrong?

Re: Self-intersecting loop

mdavis22569 — Thu, 20 Oct 2016 11:13:13 GMT

Can you share the part

overlapping ...the lines don't come together and meet 100% they cross and "overlap"

Something like this ..

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 11:17:49 GMT

So that green dot is not certain when defining a point.

Re: Self-intersecting loop

Mark.Lancaster — Thu, 20 Oct 2016 11:18:53 GMT

@Anonymous

Without seeing your information or how you did you sketch we can only speculate where the overlapping geometry is.

For example (and I only did this to show an example of an overlapping sketch) here's what Mike is referring to...

I'm thinking when you did the arc it wasn't tangent to the line or you didn't apply a tangent constrain. At certain zoom level it may look okay to the naked eye but if you could really really zoom in you will most likely fine the arc overlapped the vertical line. But we can only speculate at this point..

Re: Self-intersecting loop

mdavis22569 — Thu, 20 Oct 2016 11:22:56 GMT

@Mark.Lancaster we think and draw alike too ...lol

Re: Self-intersecting loop

Mark.Lancaster — Thu, 20 Oct 2016 11:26:00 GMT

@Anonymous

I looked at your sketch.. Not sure why you placed that other point.. But I deleted your arc, put it back in and applied a tangent constraint between the arc and vertical line. No problem and no overlapping information.

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 11:45:33 GMT

It is not said in demo that arc is tangent to the vertical line. I wish to whether it correct to assume it.

Re: Self-intersecting loop

JDMather — Thu, 20 Oct 2016 11:51:27 GMT

What video?

Does the sketch make logical sense as you have drawn it?

Did the video instruct you to add the extra sketch point?

What manufacturing process is used to create an arc to .001mm tolerance?

Q. How thick is a standard sheet of paper?

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 11:57:02 GMT

This is a video from YouTube. Just I want to replicate the work.

https://www.youtube.com/watch?v=eGCRbSfV89Y

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 12:04:50 GMT

This point in the sketch was spontaneously added when I used sketch doctor to fix the problem. Could you please explain the reason?

Re: Self-intersecting loop

JDMather — Thu, 20 Oct 2016 12:31:59 GMT

The youtube presenter clearly only has a partial understanding of geometry.

The presenter selects center point arc tool and then carefully tracks over from the end of the arc - this implies tangency.

But Inventor did not automatically add the tangent constraint and then the presenter overrode by adding unnecessary dimension and trimmed without connecting the endpoint at other end (note that the sketch is still unconstrained).

Only two dimensions and a tangency are needed.

I would eliminate the 1.651 dimension as it is fantasy anyhow.

Only the radius and the 6.35 and tangent are needed. The 1.651 will be solved by the geometry conditions. It is what it is.

Logic must be a part of the design process.

The presenter started out creating the arc using a logical process but then got lost when the endpoint did not match a rounded off calculation distance. Use geometry.

Q2. What is 1.701-1.651=? State answer in terms of ratio of the thickness of a sheet of paper.

BTW - when you cite a source of information - you should reference the timestep so that it is easy to find.

Re: Self-intersecting loop

Anonymous — Thu, 20 Oct 2016 12:30:48 GMT

Thanks