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Old 12th December 2004, 02:52 AM   #1
jerrylynnb
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Default sub-dividing in reverse?

My 1st try at modelling was a leaf. I created 3 ellipses aound the center, each one rotated (left to right) about 25 degrees from the other, with the first and last ellipse being a bit smaller. Then i selected vertex and cut the entire right half of each ellipse. Then I created a surface, which resulted in something like the leaf, but with unwanted surfaces connecting the top of the leaf to the bottom. I "cut" these surfaces, and I finally got my leaf shape, but I can't tell if it is only one-sided (if someone can help here - please do). The shape was not smooth, and smoothing didn't really do the trick, so I subdivided and then splined. That did it. A whole lot of triangles (too many, really), but the shape is smooth and something like a leaf. Now I want to get AC3D to re-model this shape with greatly fewer triangles, but, when I selected "combine", it wanted all surfaces to be adjacent. How do you get an object that is OVERTRIANGULATED to be represnted with fewer traingles that keeps the smooth shape within the resolution as is currently modelled?
What I would really like, is to be able to select REGIONS within my object to be "reverse-subdivided", because I can see which regions are way overtriangulated and which regions probably need this dense of a level of vertices. I am still learning. jerrylynnb
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Old 12th December 2004, 04:14 AM   #2
Andy
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If combine is failing, try selecting fewer surfaces to combine - they must have edges touching. If that still doesn't work, look for bad surfaces (red or blue lines) - you may need to remove these with the optimize functions (object menu).

You can use the Object->reduce function to reduce the detail although it's not predicatable and may not be suitable if your model is essentially 2D.

An alternative may be to retrace a new polygon/s over the outlines you have now.

If you can post or send a picture we may be able to give a more specific solution.

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Old 12th December 2004, 04:24 AM   #3
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BTW - if you remake your model, use the subdivide preview rather than doing a real subdivide. Use tools->Object-property-editor and in crease the subdiv level. Then you can move the vertices and see how the shape will look after you commit the subdivision.

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Old 12th December 2004, 02:33 PM   #4
Stiglr
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I've found that you can't underestimate the power of "doing it yourself" where surfaces are involved.

When the automatic functions fail to produce results, I've had good success with copying and pasting groups of vertices, resizing/scaling/positioning the copy relative to it's neighbor, merging the original object and the new vertices into one object, and then, 3 vertices at a time, counter clockwise, creating the faces between the vertice groups. It takes a bit longer, but it almost always does the trick, and creates no "mess".

When creating tricky things like canopy rails, turret frames, wheel wells, wingtip edges, and things of that nature for aircraft, it seems to be the ticket. I'm through with messy, unpredictable Booleans and automatic subdivides.

With your leaf, it sounds to me like you need to add some vertices towards the center of the leaf, to offset the shape a bit and add some "depth" or dimension. This might also stop the auto functions from drawing big triangles all the way across the leaf from the base to the farthest tips.

Or, try this: You could grab all the vertices from your original elipses, Surface/Remove Surface Only and then Vertex/Convex Surface Object, and see if that helps. It might still create that "overtriangulated soup" you talk about, too. When creating cockpit glass panes based on the inside of canopy rails, I get extra faces I later have to remove, so that I end up with one, flat surface. If that's the case, and it gets too difficult to determine which superfluous faces to remove, then try it the way I outlined above.
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