[article] Curved Geometry along Curved Surfaces

This is a discussion topic for the article "Curved Geometry along Curved Surfaces" by trepid_jesse which can be found here

Article description:

Creating curved geometry using arches

Good tutorial, you explain most of it pretty well and back it up with good images. I can picture a lot of people getting lost at a couple of the steps, but this is some fairly complex brushwork so its to be expected.

One thing of note is that in the last picture of step 3, the lengths you mark out aren't all correct. You say the diagonal internal lines are 6 units long, but that isn't quite the case seeing as they are crossing the diagonal distance of 3 squares, which is closer to 8.5 units. Not a big deal or anything, but it does mean that the centre parts of your arch are thicker than the parts towards the ends. This would be important if you were creating an archway trim or something as it would throw off your texturing, but for a curved archway such as this I can't picture anybody noticing.

Excellent just what I needed!
I thank you lots!

Yeah, I was somewhat hesitant about labeling them that way too, Reno. I figured it would be better to label them that way to possibly alleviate any confusion from the statement, "[...] the width between each point on the base arch is preserved around the edges of each profile arch;" albeit, it's a mathematically incorrect statement. I had planned on pointing that out in the "Caveats and Other Information" section, but forgot by the time I got there.

Ah, ok, tutorials can be edited, and I brought up in the last section of the tutorial.

Thanks for reminding me, ReNo.

Had me confused for a bit, but I figured it out. Very good!

Did a lot of that in my fairytale level

Overal a nice tutorial, though I find the bit where you are actually making the smoothed part of the arch fairly fast-forward.

I am thinking that there might be an easier way to accomplish the same structure with displacement surfaces. I haven't experiment with this alternate approach, so I can't say it's entirely feasible.

But good tutorial, nevertheless.

Its very hard to use displacement surfaces with any degree of accuracy however, hence why they are better suited to somewhat rough (inaccurate) features like terrain. Its entirely feasible you could use them to make something like this, I just don't think it would be easy. In fact, perhaps the best way to make this using displacement surfaces would be to build it as in the tutorial, and use it as a reference for shaping your displacement.

There's an easier way to do this that I learned during my "HL1 Days", heh. I'm not sure if it would be appropriate to write another whole tutorial for it though. But I know it's substantially cleaner and less work than this method. The gist of it is in this diagram from a few years ago:

http://www.snarkpit.net/pits/campaignjunkie/pipeturn.jpg

Basically you vertex-manipulate trapezoidal prisms so that they have even slopes, as seen in the diagram. But hey, trepid_jesse's method works, and as he states in the beginning, that fact is pretty important.

Very nice, I always have a hard time when I have to make odd shapes like this you really have to plan out what you are doing. I'm sure many a noobs will find this helpfull.

Nice nice

Impressive, and very smart, using the .45 degree angle you wont get any invalid brushes if you do it right. I wouldnt have come on this myself.

Thanks, pepper, but I thought I'd put out that the reasoning for using a 45 degree line for interior edge is to ensure that each section of the profile arch corresponds to a section of the grid. This makes the arch retain a uniform shape as you progress through the arch.

Step 4 is what will help you to not create invalid brushes, and because of what was done in Step 1 life is made much easier.

Thanks for all of the comments, though, from everyone.

I dont think that you would need to split the whole arch in triangles. I can do it wihtout all those triangles:
http://www.xs4all.nl/~dewitnel/peppersplanet/arch.jpg

You don't even need the arch tool:
http://img217.echo.cx/img217/6269/smoothwire8fk.jpg

Not bad...bit hard to understand =S

"after creating the full 180 degree arch, I made it into one brush. "

We can do that?! How?

Yes I was wondering that also.

I assume he created one brush and clipped it or otherwise manipulated it, using the arch as an example. In all my 6 years I haven't seen a 'combine brushes' tool either. :P

Yeah, sorry about the confusion.

At any rate, I've since learned that this kind of brushwork is pretty much pointless. I suppose it could still be useful for some situation, but barring using a model for the geometry you can create much more "eloquent" curved surfaces using displacements.

Care to make a tutorial or explain how to do this with displacements? :?