Joining curves actually Merges them instead. Ouch. New in R6?

So why is Join (curves) actually Merging them?

I often want Join and then be able to Explode. I also often want Merge, but now it seems I cannot decide which of the two will happen!

I recall R5 only joined curves (could be exploded again). But Merging curves was difficult although sometimes desired. As I see it Merging and Joining are two useful but different use cases, but now they seem to be conflated.

Or is there something I can do to prevent Curves from Merging on Join?

// Rolf

Hi Rolf - Joining should not merge but joining, moving a control point may make an unexplodable curve. That is not new, however.

-Pascal

Hm. So that must then have happened then.

But what is maybe even worse is that Join modifies the structure of the curves (becomes more complex):

Fig. Before and after Join:

Above I had planned to get four control points for every surface section when extruding this curve. But I can of course extrude before joining, and Join the surfaces afterwards. I really thought this had changed since R5, but if you say so I must believe you.

// Rolf

Hi Rolf - joining has to make the curve the highest degree of the input curves - this will make lower degree curves more complex looking… that is also ‘how it’s been since the dawn of time’, though, I’m told, there is a way to avoid this, technically…

-Pascal

Ah, I should have understood this!

Apparently I didn’t try very hard to make simple surfaces in 2016 when I first tried to do some surfacing, so now all the tricky bits floats up to the surface when I actually try to simplify… :grinning:

If you want to keep your extruded surfaces as clean as possible, you can also first extrude the individual curves, then merge the surfaces into a single surface (yes, a surface, not a polysurface) with the “Smooth=No” option. This way, you can simplify the geometry, especially when you have to deal with intersecting surfaces or polysurfaces for Bolean operations or fillet edges.

The following is a very good example showing where that technique solves a problem that occur with surfaces that were joined instead of merged.

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Yes, that is my strategy for now.

What I had already drawn some years ago was, among other things, a car grille which at the time looked OK in my eyes:

but a closer look at the surface structure reveals the ugly truth:

So I try to make better (simplified) curves as to recreate some parts with cleaner surfaces. Working on it.

An old Swedish beauty in the making:
image

// Rolf

Ah, I see - the fender query now has context.

-Pascal

Yes. :slight_smile: Same thing there. But I will fix it sooner or later. I’m adventurous you know…

// Rolf

Took another stab on it. Surfaces bent and curved in all directions but now very much better, much cleaner structure. Getting there.