Slash and Spread Entity

[wildspidee]

I am working with hand drawn pattern instructions and converting them to CAD, so this may seem a bit odd. I've attached a drawing to illustrate.

If it was paper, the original pattern would be slashed at the Center Front line nearly to the other edge, then the pattern is spread out. The edge line retains its length and the individual sections retain their width.

I've tried different combinations of tools in QCAD, but I end up distorting something in the process. I'm sure this isn't a one-step process, so whatever it takes to accomplish this is fine. Any suggestions?

Screenshot_1_23_13_12_57_PM.png (91.41 KiB) Viewed 533 times

[clive]

Firstly have you got any cad files so far on this pattern that you could attach here on the forum? - and, to clarify if we look at your drawings here for a minute, am I correct in thinking that the top image (no. 1 in my photo) is your starting point and then no.2 is the showing the top pattern slightly curved? Is no.2 drawing trying to show this?

pattern question 1.png (101.67 KiB) Viewed 529 times

[wildspidee]

Yes, that's exactly right. I know it's difficult to visualize. If this pattern was a piece of paper, the green areas in #2 would be the table that you can see because the cuts have been spread out. The Center Front line is now a curve that has a lot more length than the original line.

Here's a quick DXF. I just brought in the drawing and used it to quickly sketch out the main entity. Both are included in the file. I hope that helps.

Please let me know, if I can provide anything else. I appreciate your efforts.

[clive]

The last section isn't exactly correct but is this what you mean?

Slash and Spread Entity test 1.png (27.01 KiB) Viewed 502 times

[wildspidee]

Yes, that appears to be just perfect. The length of the left side has been preserved. The distance in the slashes is not fixed, it can be variable.

How did you manage it?

[clive]

How did you manage it?

Not that easily

But, I hope you can understand the following:

1. Draft your basic shape.
2. Select everything and use the Modify > Explode command, to break up any splines into smaller segments.
3. Now use the Modify > Divide tool to break any splines or lines at the exact points – in order to define exact boundary areas for the individual sections.
4. Now select and create Blocks out of the individual sections. When you have created the first block (working from the top down, as it were), make the block invisible and draw in another line to replace the line that was previously used for the last block (you’ll understand this bit when it happens!).
5. Continue like this creating blocks.
6. Lastly with all the block showing -use the Modify ‘Rotate’ tool and manually rotate the blocks to the required new positions (use the small pick arrow for this to rotate manually!).

Job done

[wildspidee]

I understand everything. I tried something similar, but I didn't explode the splines and was using layers instead of blocks. I will give this a try today.

QCAD to the rescue! Now I just have to perfect the technique enough to do a tutorial on it. That will be fun.

Thank you so much for taking the time to figure this out, I know it wasn't easy. At least its is doable, and that's the most important thing to me.