View Full Version : Trimming Elements

05-14-2001, 11:30 AM
Excuse me if my terminology is incorrect, but hopefully someone will be able to decipher this...

I figured out how to reduce the number of elements in an imported .dxf file, but what I end up with is a series of broken elements. There is a gap between them. When I go to generate the .sbp code, I get z-ups between the small segments.

How do I connect each of these small parts into one contiguous chain?

It seems like I've tried all all of the different tools within Vector.

I initially selected the object with shift>click then ran it through draw>spline>arc spline. Then I hit "T" while chain is still selected.

Any help?

Aaron Savka

05-14-2001, 01:42 PM
Try Change reorginize. That can help in some cases. Also Vector can only work with what you have given it. Are all you lines going in the same direction (i.e. ccw or cw)? I have read some posts that indicate that polylines from other programs have to be exploded before you export. What program are you getting your dxf files from?

You can email me a dxf file and I will see what I can do with it.

John Forney

Gerald D
05-14-2001, 02:06 PM
Aaron, see "Vector CAD/CAM: SHIFT Select to create cut order - WOW!" thread, and in particular Bill Young's post of 6 December 2000.

05-14-2001, 02:32 PM
Tips worth a repeat:

typically when you are drawing something in cad you always seem to miss an object, so you add it later. Big problem, 'cause there doesn't seem to be any way to get this puppy to cut the way that you want. I saw someone say on this forum that they finish everything off and then cut and paste everything off the material area by a set amount and then paste it all back in the proper order. Bummer! Well I just found out from that nice Fred guy that you can de-highlight everything and then hold down the shift key and select EVERYTHING in order. This even applies to single lines! If you do this (always shift clicking) the order that you choose is the exact order of the cut file generated by the NC doodad. Wow! I just designed a table top for a vacuum system with a boatload of horizontal lines, vertical lines, diagonal lines and eight cut out holes for the pipes. Too easy. You can even grab a bunch of associated lines (such as all horizontal in a 2' square grid) and tell it to reverse every second.

The Shift-select thing is slick, isn't it! I got a drawing the other day that was drawn completely with arcs( 300+), and the order they were drawn in seemed to be pretty random. Shift-selecting them linked them all together and created one toolpath.

One trick I learned while I was doing it. Even though the arcs looked like they were touching at their ends, occasionally there would be a TINY gap between the arcs that would cause a break in the chain. If you go to the SPECIAL menu, then OPTIONS, then click on UNITS, there's a setting at the bottom called GENERAL ACCURACY. The default was something like .00004". I changed it to .005" and everything linked up just fine after that.

If you think that is cool, just wait until you figure out the pocketing and automatic Z movement functions

If the gaps are big and a straight line will bridge the gap OK, click on SPECIAL, Then OPTIONS, then TOOLBARS, and select the CAM toolbar. Now click on the two entities that have a gap between them and click on the icon on the far left end of the CAM toolbar. It will draw a line connecting the two entities.

One trick though. You have to make sure that you select the two entities so that the arrows showing the cut direction are going in the same direction. If not, the connecting line will connect the wrong ends.

Yes, you can reach that same toolbar by right clicking in the gray area just to the right of the 'simulate selection order' button on the main toolbar and then selecting 'cam'.

I'll often be so close in on the area that I can't even see the arrow directions so I'll just click on the lines knowing that they are pointing towards each other then just hit F5 to reverse the direction of the last line selected. This way I know that not only are the lines pointing in the same direction, but are in the correct sequence. Instead of using the toolbar connect lines button though, I usually just use the shortcut alt d, l, c, which is the same as Draw-Line-Connect.

Be very careful in changing the general accuracy. Be sure to change it back when you finish what you are doing. Strange things can happen.

If you change the general accuracy, does it apply to only that file or does it change the accuracy in 'general'. I changed that setting for a file just to see how it worked, but now can't remember exactly which file it was. The last time I started Vector I re-checked that setting and it was back to 0.00004". Do I have a little time bomb in one of my files now?

Thanks for the advice; Vector always reverts to the default when I start it up. I can understand why there are times that you wouldn't want to lower the general accuracy, especially in 3d files, but sometimes I get 2d dxf files from customers that are only saved to 2 or 3 decimal places, and lowering the accuracy setting makes them easier to work with. Does it cause problems other than just lowering the accuracy for that toolpath?

In talking to Fred, I think that too low an accuracy can cause items to be selected in strange ways.
As far as always reverting, if you go to special-options-defaults you can change items in vector and then save to custom so that you don't need to change inputs to suit you on each drawing. When I do this, I start with a blank file and save to custom only one thing at a time. (i.e. open a new file change another then special-options-defaults- save to custom) That way I don't have some unintended changes. Easier to handle for those of us that are intellectually challenged.

I have changed my pocket and approach items and dimension attributes to better suit the way I work. Also the connect at z options can be changed. Just start a simple drawing and connect at z, special options defaults save to custom.

As a note, if you want something out of the way to better see another part of your drawing, you can select it (either by clicking or edit select)and then go to change attributes blank. I was cutting it then pasting but blanking also works.

Thanks for the tip on saving settings. There are several things I've been doing every time I use Vector like maximizing the drawing window and changing the z-axis settings, and it's good to know that these settings can be saved.

05-14-2001, 05:07 PM
Aaron, instead of hitting T for trim, use Draw Line Connect instead. Change Reorganize will eliminate some tiny lines that may be drawn on top of each other, and when it is done, your geometry will be selected in a sequential chain, even if it was not originally selected that way.