Help please - stopped grooves in SketchUp?

[Eric The Viking]

Yes I kept getting a raised bit as if it was tilted back.

That was the reason for the tiny rotations of the circles/arcs. Sketchup doesn't do genuine curved objects, but approximates them with polygons (flat) or polyhedra (3D). Follow-me doesn't like this, because it sees a follow-me lathe line that isn't perpendicular to the template it's using. If you do the tiny rotations, by the right amount and at the right point in the process, the problem goes away

But Schultzy's solution is way, way better than where I was starting from, and avoids the pitfalls.

E.

 

[Brentingby]

What Follow Me does is mathematically correct but is sometimes not what you expect.

As I said, there are times when you still need the method Dave Richards shows with rotating the circle by half the angle between vertices. As an example, draw a demilune table top and put an ogee profile on the curved edge.

 

[Graham Orm]

Yes I kept getting a raised bit as if it was tilted back.

That was the reason for the tiny rotations of the circles/arcs. Sketchup doesn't do genuine curved objects, but approximates them with polygons (flat) or polyhedra (3D). Follow-me doesn't like this, because it sees a follow-me lathe line that isn't perpendicular to the template it's using. If you do the tiny rotations, by the right amount and at the right point in the process, the problem goes away

But Schultzy's solution is way, way better than where I was starting from, and avoids the pitfalls.

E.

I sussed that Eric and tried it, but only once. I did the rotation, but obviously not correctly.

 

[Shultzy]

PS: I'd been dreading later in the month, when my eval. copy of SU Pro expires and drops down to SU Make. I can't justify a full licence. All this is very confidence-boosting though, as the biggest missing piece would be the set of Solid Tools, but it looks like you can do pretty much everything without them, just thinking it through and taking a few more steps.

Thanks for the nice comments. I still use v8 and unless you are going to use it professionally the pro version is not needed. I haven't found anything I can't do in v8.

Here is a drawing of a Rolls Royce Silver Ghost, note the seats which were very difficult to draw.

 

[Graham Orm]

PS: I'd been dreading later in the month, when my eval. copy of SU Pro expires and drops down to SU Make. I can't justify a full licence. All this is very confidence-boosting though, as the biggest missing piece would be the set of Solid Tools, but it looks like you can do pretty much everything without them, just thinking it through and taking a few more steps.

Thanks for the nice comments. I still use v8 and unless you are going to use it professionally the pro version is not needed. I haven't found anything I can't do in v8.

Here is a drawing of a Rolls Royce Silver Ghost, note the seats which were very difficult to draw.

Wow!

 

[Eric The Viking]

Ditto!

I'd still be using SU 8 but for it stopping working recently under Linux. So far I've had no real issues with SU 2015 (64-bit). It seems very well behaved actually. I dipped a toe into Ruby plugins yesterday, and the ones I've loaded also seem to work without issues. Ruby was one area that didn't behave well (under Wine) in the past. The only two niggles so far are that I can't get any internet-related stuff to work properly. That includes the object warehouse and direct-download/install of plugins, but neither are showstoppers. When it starts up it spawns a browser window, but doesn't go to the correct page. Again no biggie.

So I'm now catching up on a lot of things I'd put to one side - won't be doing Rolls-Royces though - the competition is way too steep!

 

[Brentingby]

Shultzy, that is a great model of the Rolls Royce. Nice work.

EtV: Do you have Internet Explorer installed? Or can you install it? SketchUp uses Internet Explorer on Windows and Safari on Mac for web dialog operations such as 3D Warehouse and Extension Warehouse. There are a number of plugins that also use web dialogs that require one or the other. And it doesn't matter what your default browser is for looking at the web. SketchUp only uses IE and Safari. They do that because those are the only browsers they can be assured are present.

 

[Eric The Viking]

Hmm. Not sure.

I'm surprised Trimble doesn't just pass something to the default browser.

It's a while since I ran IE on a PC. I'm morally certain that SU 8 called Firefox without any problems. I had a few programmes that tried to call IE, but they usually didn't work correctly as it wasn't maintained.

 

[Brentingby]

No. I assure you, SketchUp uses only IE or Safari. They do not use your default browser if it isn't one of them. So for those using Windows or Mac, it's important to keep IE/Safari up to date even if you don't use them for browsing the Internet.

 

[xy mosian]

I do not like to disagree. However Sketchup 2015, make by now, has just accessed the on-line help via Firefox. I do have IE installed, but not used, which may account for this.
BTW brilliant work all around on the original quest of this thread.
xy

 

[Brentingby]

Online help is different from the web dialogs used to access the 3D Warehouse and Extension Warehouse.

In fact you can read about it in the Knowledge Base. Here's one entry.

To connect to the Internet, SketchUp uses Internet Explorer even if you have a different default browser.

I'm not trying to be argumentative but it is the way it is.

 

[Shultzy]

As an example, draw a demilune table top and put an ogee profile on the curved edge.

Brentingby, you can create the above using my method. Isn't a demilune table top just a semi-circular table top, unless I should be thinking of something else?

 

[Brentingby]

Where would you start the profile if you draw the semicircular top with the Arc tool?

 

[Eric The Viking]

Where would you start the profile if you draw the semicircular top with the Arc tool?

That's an interesting question!
Based on what I've just learned, at some point on the main curve where the profile can be genuinely perpendicular to the line, I'd guess.

If you use the Arc tool -- quadrants, arcs and so on -- you seem to get a vertex (corner) at each end, so using Follow Me at that point will cause the oddities I've been getting. But there's another "gotcha" too: assuming youi initiate Follow Me cleanly, the ends won't be square to the curve either (as the last sides of the curve aren't).

So I'd guess, in order to make it work nicely, you still need to draw a circle and rotate it, then draw a chord, that exactly bisects faces of the "circle's" polygon. Once done, delete the major arc, and you have your demilune tabletop outline.

It seems to be a good rule to regard all Sketchup circles as polygons that have to be managed as such until you're done.

On which note, I have a follow-up question about smoothing but I'll start a new thread...

 

[Brentingby]

If you use the Arc tool -- quadrants, arcs and so on -- you seem to get a vertex (corner) at each end, so using Follow Me at that point will cause the oddities I've been getting. But there's another "gotcha" too: assuming youi initiate Follow Me cleanly, the ends won't be square to the curve either (as the last sides of the curve aren't).

Exactly.

 

[xy mosian]

Online help is different from the web dialogs used to access the 3D Warehouse and Extension Warehouse.

In fact you can read about it in the Knowledge Base. Here's one entry.

To connect to the Internet, SketchUp uses Internet Explorer even if you have a different default browser.

I'm not trying to be argumentative but it is the way it is.

Clearly my mistake.
I admit to not attempting to access either the 3D Warehouse or Extension Warehouse.
xy

 

[Brentingby]

No worries, sir.

If you are using Mac and access the Knowledge Base it will substitute Safari for Internet Explorer.

 

[Shultzy]

Where would you start the profile if you draw the semicircular top with the Arc tool?

I've encountered these issues before when dealing with arcs. I think its because the "followme" tool expects the profile to be square to the first line its going to follow. This happens when its a circle but not when its an arc. I usually get around this issue is by creating an intersecting rectangle, intersect faces and remove what's not needed.