ok, your screenshot didnt show that, but if thats already in, thats great.
yet if you want those tunnels... not connected tunnels should already be easy to do, right? just mold a hole.

now if you want a cave with two entrances, or maybe even more, imagine this:
you make two tunnels in your landscape, and you bend the endpoints together. if you have this picure in your mind, its obvious youre going to need to knit these two tubes together by, in the i think easiest way, taking away the patch at the very end of both tubes, and connecting the four open edges with those on the other side.
but i dont know if this way of working will go along with your other routines, like the rendering. it will surely ask a little more from your gui to get such a thing working in an editor...

Yes, and this is what I assumed I could do all along.

I get to the stage where I have two deep caves that end at the same four points, and then delete the two patches made from those four points, but the problem occurs when I try to make it continuous.

It's hard to explain, and hard to visualize (which is why I mistakenly assumed I could do this) but consider this diagram:



Say each intersection of two lines makes a control point. Using these sixteen control points we can draw a catmull-rom patch in the middle square. Also assume that there are more control points around the drawn box that determine the structure of the remaining 8 patches.

Say we delete the middle patch, and we want to build a tunnel around the edges of the patch (going up out-of-the-monitor).
So we add four more points above the points [1][1], [1][2], [2][1] and [2][2] that define the basic area of the new patches and four more points above these.

To build the bottom side (the patch spanning across points [2][1] - [2][2]), it would have points [3][1] and [3][2] as it's bottom points. The top points would be made from the new points added above its basic points.
The point [1][1] and the new point above that as it's left points. The point [1][2] and the new point above that as it's right points.

But what about the corner points?

What the heck do I assign for these?

Sorry like I said it's hard to explain

It doesn't seem possible to maintain continuity


EDIT: made the diagram an image cuz my ascii picture didn't work


[edited by - nexius on May 6, 2003 6:23:35 PM]

rather than have the caves end at the same points, can you just delete the end patches and make new patches to connect them?

if not, switch to a different subdivision scheme maybe? i know for a fact that fitting cubics with slope constraints across the patches will work.

quote:

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Original post by Anonymous Poster
rather than have the caves end at the same points, can you just delete the end patches and make new patches to connect them?

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This simplifies things, but it still appears impossible to make continuous.

quote:

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if not, switch to a different subdivision scheme maybe? i know for a fact that fitting cubics with slope constraints across the patches will work.

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Ya, it appears this is the only way. What do you mean slope constraints? Something like N-Patches? Please elaborate, as I would really like to achieve this effect!