simple (or not?) intersection question

If you have two enitites. Like two spheres. And you wish to make an intersection BUT you don't want that the other sphere is erased automaticaly upon using the intersection command.

How to accomplish that other then copying the other sphere and replacing the deleted one with that copy? Simpler method, if any? Some system variable?

Anybody?

I do it the way you described, but I copy one of the spheres onto itself before running the command. (ie-centerpoint to centerpoint)

Then when I run the command, I select one of those spheres, careful not to select both of them.

I do that a lot with the subtract command, because I use it for downlight mounting holes in ceilings, plus ceiling skins that overlap... I don't want to accidentally join those ceiling layers by subtracting from them in a single operation.

The other way I do it is to save the subtraction entity onto the copy with basepoint command, so I just paste a new one at the end of the subtract command (by pressing Ctrl-V).. It's good for when you've got like 25 lights in a row that you have to do it with.

What about the system variable DELOBJ? Try that.

I was wrong, I didn't mean on intersection command, but on substraction cmd.

thanx all for answers, though

Nice, thanks! As soon as I finish the render I'm doing, I'll definately check that out!

Here are the settings for it:

http://www.kxcad.net/autodesk/autocad/AutoCAD_2008_Command_Reference/d0e136264.htm

I don't know if it's on R2004, but I'll give it a shot.

(I thought you meant the interference command, rather than intersection)

If I understand your question, you could run the INTERFERE command. It will create an interfere solid. Then subtract that from the one object and the other object will still be whole, and directly up against the first object. The pics attached should tell the story. Interfere is a pretty good command, but all the books I recently learned from talked about intersect, union, and subtract. Not much about interfere. It's a shame, b/c there are many times I use it.

The other way I do it is to save the subtraction entity onto the copy with basepoint command, so I just paste a new one at the end of the subtract command (by pressing Ctrl-V).. It's good for when you've got like 25 lights in a row that you have to do it with.

Like MikeScott eludes, I keep a layer in my 3D solid model that I entitled "interference subtractions". Inevitably, I uniformly space some cylinders along an edge to serve as screw holes in a cover. Then the spacing changes due to some factor. As I work in 2002, moving the holes already in a solid sometimes get goofy on me. So rather than creating the solids, and subtracting them out and losing them, I use the interfere command, and then throw the original solids onto that layer, should I need to put the same pattern or size screw hole somewhere else on the assembly, and mirror or other options aren't ideal, then I have all the right solids to interfere and then subtract out. I don't feel like I am always being the most efficient with my hole making, but this method always serves at least as a work-around if all else is failing.

Yep, this is pretty much the thing I was looking for. I'm a newbie in ACAD 3D so thanks!

Like MikeScott eludes, I keep a layer in my 3D solid model that I entitled "interference subtractions". Inevitably, I uniformly space some cylinders along an edge to serve as screw holes in a cover. Then the spacing changes due to some factor. As I work in 2002, moving the holes already in a solid sometimes get goofy on me. So rather than creating the solids, and subtracting them out and losing them, I use the interfere command, and then throw the original solids onto that layer, should I need to put the same pattern or size screw hole somewhere else on the assembly, and mirror or other options aren't ideal, then I have all the right solids to interfere and then subtract out. I don't feel like I am always being the most efficient with my hole making, but this method always serves at least as a work-around if all else is failing.

Nice! You think YOUR way isn't efficient? I always end-up unioning stuff to it until I cover the holes.. My way is HORRIBLE.. lol I'll give yours a shot, sounds good!

Nice one Crazy J, thanks for that, I tried it myself and it was pretty good rather than using intersect command in some other purpose...

Nice! You think YOUR way isn't efficient? I always end-up unioning stuff to it until I cover the holes.. My way is HORRIBLE.. lol I'll give yours a shot, sounds good!

Thanks, but there are times when I too have to do what I think you are talking about. I had a frame and two covers, and even a reinforcement layer on top of one of the covers and had the holes all in it. Then, the team changed all three dimensions of the frame. So I had to reconsider all the spacing. I'm not sure what I've done, but on some components, I can use SOLIDEDIT and then DELETE or MOVE out of there. Then other times, I can't get the holes or features to move or change or delete at all. I figure it must be something in the way I created the solid, but I have not figured out what yet. This is my first real 3D solid modelling project, and I have learned a ton in the six months I've been doing this now. So on some of the original first components I made, I am sure I did things that were not ideal, and they coul be causing me the trouble now.

So, there are times when I can't get the holes to go away or move, and so I create a new BOX over the area, do UNION, then redo the holes with my method above. I kind of came up with that method out of my troubles I've described here. But it drives me nuts b/c this should be an easy thing to do and with it only being a sometimes problem, I'm still scratching my head. Covering in the holes with a new box is like my kids using half a roll of scotch tape to put two sheets of paper together when they could have used a stapler.

Yep, this is pretty much the thing I was looking for. I'm a newbie in ACAD 3D so thanks!

No problem... I find myself drawn to making quick little geometrical objects like that. I'll sometimes set things like that on CONTINUOUS ORBIT and leave it running. It messes with the kids' heads. It's neat to see how each of them have a different level of development of their spatial relationship skills.