Convert a curved shape into lines or triangles

[labmonkey]

Hello, this is my first post, so I hope this is the place to put it. If not, perhaps you could tell which subforum to repost. I have tried searching for similar topics without success.

 

I'll explain at the end of this post the problem in more specific detail, but I will generalise it to begin with because I don't think the specifics are important.

 

I have a 2D drawing that contains many curved shapes (a ring shape, i.e. one circle subtracted from a larger circle) as well as regular polygons. For a technical reason I need to convert the curved shapes into simpler objects, either lines or triangles.

 

My idea was to make an array of closely packed lines and then subtract from these lines the ring shape. This would then leave me with an array of parallel lines in the overall shape of the ring. However, the SUBTRACT command does not work with lines as far as I can tell. Does anybody know if there's a similar command that would subtract from a line? (By the way, I could not use narrow rectangles instead of lines because the resulting shapes would have slightly curved edges.)

 

Edit to include this picture, which probably explains better than the text above. I want to change the left shape into the right set of lines.

 

An alternative way to do this would be to convert the ring into several small triangles. Does anybody know a simple way of doing this?

 

Another minor point is that I am running a Japanese version of autoCAD (because I work in Japan), but my Japanese is not very good, so if you have any suggestions, could you refer to (English) command line commands instead of the menus?

 

Ok, now more specific information in case it's needed. The drawing is a feedline with several curved resonators attached. The ring shapes are actually just half of the ring shape, which are attached to two rectangles to make a "U" shape. I intend to "print" this drawing onto a semiconductor using an elionix electron beam machine. The problem is that the elionix's software cannot handle curved shapes - it can only handle lines, or polygons of up to 5 sides. If I had a series of closely packed lines in the overall shape of my drawing the resulting "print" would look exactly as the original drawing. Likewise, if I could convert the curved shapes into small enough triangles the result would look the same.

 

Many thanks.

[GE13579]

Is EXTRIM any use?

 

Also I'm not sure if you couldn't just BHATCH then delete the circles?

[stevsmith]

Just use a Hatch inside the circle and delete the rings as GE says.

[fuccaro]

The SUBTRACT command will work if you transform your shapes in REGIONs

[labmonkey]

Is EXTRIM any use?

 

Also I'm not sure if you couldn't just BHATCH then delete the circles?

Thank you (and the other responders too).

 

The BHATCH works in general (although I'd need to check it in more detail, particularly whether there is fine control of the line separation). However, in this specific case I cannot use it because the software I am exporting it to cannot handle the result (I tried). (Edit: Probably the EXPLODE command will solve this.)

 

I also tried using the SUBTRACT command having first transformed all the shapes (i.e. lines and circles) into regions, however, it did nothing.

 

The great news is that EXTRIM does the job. The difficulty was finding the command. For any future readers of this thread, if typing EXTRIM into the command line gives you an error, you need to install the express tools (easiest way is via the add/remove programs of windows).

 

Edit: I had an additional problem with the fact that I could not use the EXTRIM command with regions, which eldon below gave me the idea how to solve. (For the above ring shape example regions are not needed, but in more complicated designs they might be.) All that is necessary is to use the EXPLODE command to explode, for want of a better word, the region first. Then you can use the EXTRIM command.

 

Once again, thank you all for taking the time to answer.

[eldon]

Perhaps it can't handle the hatch because it is an entity. If you want separate lines then you could EXPLODE the hatch, but keep it to yourself, because exploding hatches is not considered to be a proper way of working

[labmonkey]

Perhaps it can't handle the hatch because it is an entity. If you want separate lines then you could EXPLODE the hatch, but keep it to yourself, because exploding hatches is not considered to be a proper way of working

Wow, that was quick! Thank you very very much. I haven't tried EXPLODE with the hatch yet, but this command worked with my final question above. (I'll edit the above post in a minute to let people know how to do what I did.) What a great command, even if it isn't the proper way of working.