Posted by sunggus on
URL: https://forum.librecad.org/Hatching-always-failed-working-with-ellipse-and-line-tp5716011.html



Hi,

I am just new with LibreCAD, but not so blind in drawing. I have used this LibreCAD for months and have used almost all the functions/tools, include using HATCH, ELLIPSE and LINES. Here is what I did that got problem:

1. I drew ellipse with center coordinate 100,100 with major radius=8 and minor radius=6.
2. I drew the 2nd ellipse with center coordinate: 200,100 with major radius=8 and minor radius=6.
3. From 100,100 (center of the first ellipse), then I run command (to draw line with relative coordinates):
- @8<90
- @100<0
- @16<-90
- @100<180
- @8<90

4. Then I divide the ellipse ellipse I divide (with Divide command) just at the end of the lines corner.

You know, that intention is to draw something like pipe that seen from a point of view (from the right side). To make it representative, I need to hatch the part so will show the hole. Then both the long lines, the left side of both ellipse I clicked then I hatch. But got problem as the comment in the command line pane said:
Invalid hatch area. Please check that the entities chosen form one or more closed contours.

I have tried to create polyline from those four segments, but also failed, even to create polyline also failed. Trust me, I have tried so many times.

Then I zoomed every connection to make sure that still any open contour, but no one I found.

Then I have tried the same work but with major radius=40 and the minor radius=30, and I FOUND that they are working.

So, what is the problem to make close contour with the small ellipse?

Appreciate your help in this case. I wonder that there is wrong algorithm here. Please remember that I used relative coordinate here when drawing the lines rather than using snap. But however, snapping also I have tried several times and didn't work.


Another thing:

If we check the comment in the Command Line, the comment is:

Hatch failed due to a gap=2.70516e-06 between (200, 78) and (200, 78).

There is a very small gap in the same line.

Best regard.