Join two nodes just creates a mess!

[Chezqui]

I have a line and a curve. The curve is a circle that has been halved. The line is... well a line. I use the node tool and shift - select the two points. I try close curve and join curve. Both methods send a line processing from the curve instead of simply joining the two points.

[Pšenda]

Before Join curves try Reverse curves for bottom curve. 

[R C-R]

In the first screenshot, the layer named "Rack Main Frame" is a Curves layer (note the plural form). That means it consists of more than one curve. If that is showing the 2 items before you did anything to them, that is probably why you are getting strange results.

[Chezqui]

On 9/8/2020 at 9:22 AM, R C-R said:

In the first screenshot, the layer named "Rack Main Frame" is a Curves layer (note the plural form). That means it consists of more than one curve. If that is showing the 2 items before you did anything to them, that is probably why you are getting strange results.

English is a wonderful thing aint it.
Can you elaborate please. 

 

[JimmyJack]

16 hours ago, Chezqui said:

English is a wonderful thing aint it.
Can you elaborate please. 

 

It ain't the "curves" thing.

Everything is acting as it should with what you've got going on.
The whole image is something more like this yes? And your trying to "cap" that bottom gap on the left.

A couple of things need attention.
As you can see in the closeup images in your first post the two selected nodes on the left are not perfectly aligned vertically. The bottom node is just slightly to the left.
But more importantly, the two nodes at the bottom of the straight lines are smooth nodes (they show as circles). So when you go to do the Join, the bezier handle is creating the weirdness in your second image. Fixing the alignment might give a decent visual result, but the Bezier handles will still be pretty wacky.
To avoid that, convert those Smooth nodes to Sharp in the context toolbar. They will show as squares and you should be fine (do this only if those lines are truly straight. If you need to preserve some kind of curvature above which we can't see, do the join with the Smooth nodes and then delete the unnecessary long handles individually (Alt clicking on them).

[firstdefence]

Another option is to do away with the method you are using...

1. Join and close the shape with  square ends.
2. Create an ellipse the same width and move the ellipse to the end of the closed shape so it overlaps and snaps by half
3. Geometry add both shapes.

 

Geometry: Add

[Alfred]

If the scenario is as @JimmyJack has suggested, I would start with a round-cornered rectangle, convert to curves, break in two places and delete the unwanted bottom portion:

Now expand the stroke, change the right-hand nodes to sharp nodes and delete the extra node to make the end flat:

Finally, swap the stroke and fill colours:

If you want an open end on the right-hand side, you’ll need to break the curve there so that you can discard the flat cap.

[Chezqui]

On 9/8/2020 at 9:22 AM, R C-R said:

In the first screenshot, the layer named "Rack Main Frame" is a Curves layer (note the plural form). That means it consists of more than one curve. If that is showing the 2 items before you did anything to them, that is probably why you are getting strange results.

 

Thanks you very much chaps - lots to consider and try.

Sorry for the late response but in frustration I have had to fire up my 13 yearly iMac and use an equally old version of illustrator. 

I flew through the drawing using so many little quirks that I have learned over the years. 

I guess I'm trying to gain that affinity with Affinity if you see what I mean.

I have to, because one day that old iMac just isn't going to fire up and I'm not getting involved with adobe again!