Intersection Problem

[andrew239]

Good afternoon,

I am having a problem lately where every now and then i cannot pick up an intersection snap point. I thought the Z values might be different, but they are all at zero. To further complicate things, i can use one of the lines to trim the other, but still no intersection snap is there. I can run the FLATTEN command, and that will allow the intersection (sometimes i need to run it twice). It is confusing, as the flatten apparently fixes the problem, but according to the properties pane, there was no problem with the z value.

I have attached a small drawing showing the problem.

thanks

intersection prob.dwg

[ReMark]

I tried many different variations of trimming using the five lines and they all worked without a problem.

 

I also checked the Z values, did an Erase > All (just to see how many object were reported back) and even ran Overkill (no duplicate or overlapping lines). I don't think there is a problem with the drawing itself.

[andrew239]

thanks for the input. did osnaps show you an intersection ?

[maratovich]

You use inches.

Inches do not give an exact result.

Run the command :

_units

Set the format to Decimal

Set the accuracy to 0.00000000

[andrew239]

coolio. Thanks heaps for the help.

[andrew239]

that did not seem to work. Any other suggestions ?

[maratovich]

What does not work ?

Have you broken Autocad?

You can not choose decimal?

Maybe you can learn Help? Look for a "seeming intersection" ...

Maybe you asked the question is not it true?

Maybe you need to reset Z to 0 ?

[dtkell]

maybe you will have better luck with "APParent intersection".

[Cad64]

that did not seem to work. Any other suggestions ?

 

As maratovich described, your lines are not all sitting at Z0. The magenta and cyan lines are at Z0, but the red lines are at Z0.00000024. That's why the intersection snap is not working.

 

When I run the FLATTEN command and select the red lines, they are sent to Z0 and the intersection snap works as expected.

[andrew239]

a-ha. Thanks for the clarification. I was only getting half of maratovich's suggestion. I see it all now.

Is there a variable that will change the sensitivity of the snap (similar to the HGAPTOL). Seems weird that they are close enough to trim with, but not get the intersection. The apparent intersection did work, but i just wanted to find out what was going on.

Thanks again.

[ReMark]

Good CAD drafting habits would go a long ways towards negating the problem in the first place.

[andrew239]

Couldn't agree more. Kinds feels like i am being judged lol. In my defense, this is a problem that has arisen only in the last couple of weeks. All of the problems are contained in files that are brought in from an outside source, typically these are architectural floor plans which have been drawn using Revit. I know very little about Revit, so I don't know if it is some issue with the conversion to a dwg file, or if it is just some intrinsic data in there that carries over. Now I know what the problem is, I have suggested we now flatten and overkill everything before we bring it into our drawings. At any rate, i really appreciate the help.

[ReMark]

Drawings from outside sources can be quite problematic. It still amazes me as to what passes for a good CAD drawing in some companies.

[maratovich]

andrew239

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