I considered orienting it the other way, but decided it didn't make much of a difference. After all, I don't like texturing models very much. In fact, I barely ever texture them.

As for what it will be, I'm not sure yet. Something interesting and Roman. I don't really have any plans since it was intended to just be a test model.

Gaieus:

Wow! Great stuff, thanks. I didn't think to get the pendentives by cutting up a sphere. Do you think that my pseudo-pendentives are acceptable as they are, or should I really try to make them proper? I don't suppose it would change the model much. I tried expanding on it a little and didn't really encounter any problems.

More fleshed out version of my original test; didn't notice any problems with expanding it, although it's still different than true pendentives.

Hi. I recently made a model to test pendentives—that is, those concave triangly shapes formed when you try to put a dome on top of four arches so it fits nicely over a square. Unfortunately, I couldn't figure out any way to make these in Sketchup except by hand. I think the model looks all right, but I'm not very experienced with Sketchup, so there may be a glaring error I'm just not seeing. I am including five pictures—three in wireframe and two with faces to give you an idea of what I did.

^This is a picture from the side of my model with wireframe and hidden geometry on.

^This is a picture from the underside looking up into the dome with wireframe and hidden geometry on.

http://i.imgur.com/UOGPM.png (large)
^This is a picture from the underside looking directly toward a pendentive with wireframe and hidden geometry on. As you might've guessed, the pendentive is hidden geometry because I wanted it to look as smooth as possible with faces on.

^This is a picture of the model from above it. It shows the outer dome and arches and such with faces on and hidden geometry off.

http://i.imgur.com/RXT7v.png (large)
^This is a picture of the model from slightly below it. It looks up into the dome and shows at least partially shows all four pendentives.

Are there any problems with my method? Is there an easier way to do it?

Hey guys! Just stopping by and sharing how the third circle came to be:

You can probably trace what I did here... I was following Jean Lemire's guide (thank you very much for that, by the way!) and found a pretty simple method. I drew the tangent of the first circle you suggested I use and then drew a line from the radius of the second circle off to the right along the red axis. I found the radius of the third circle was exactly one-half the radius of the second, so I made a line of that distance and aligned it to the green axis at the point where the tangent and the radius-line-thingy met. The other end of that line was the center of the circle, and from there I drew the shape.

That may be unclear, and if so, I apologize... I didn't bother to label the lines or anything. The only thing that bothers me is that the first and third circles don't exactly meet up, but it's understandable considering they're all using under 40 sides. It's not very noticeable from afar anyway.

The cables should be made of carbon nanotube fibers.

Just curious: what are you trying to do there? Create two intersecting pipes?

Anyone else wishing for an easy way to bisect angles?

@jean lemire said:

Hi folks.

See this SU file for ideas:

Perfect! Thank you! That helped a lot. Everything is much clearer now. Also, d12dozr, interesting plugin. I'll try it out sometime.

@gaieus said:

First of all, I would use a circle with a segment count that is divisible by ten (around the cinquefoils, there are those ten pikes or what that should conveniently adjust to the segment count of the surrounding circle). Then of course you still need some bulging - say at least 3 segments between each - that would be 30 segments for a circle. Or 40 maybe but considering the overall complexity of the whole shape, I would not go over that.

Thanks for the suggestion on the segment number; by default, I use powers of 2, but I'll go with 30. Still not sure how I would go about making the circle, though, which was my original question (sorry if it was unclear). I can't figure out how to find the center point nor the length of the radius (although I could make it if I had either). In case you're curious, I'm assuming the diameter of the main circle is 16 units.

See those cinquefoils in the corners of that window? I know how to draw those in Sketchup (I was also able to make trefoils and quatrefoils), but I can't figure out what the darn radius for the thing would be. As you can see, they're the optimal size available for a circle in the area provided. Any suggestions on how to do this? I'm still a newbie when it comes to stuff like this... so help is much appreciated. Thank you!