Polygons

Is it possible to build a polygon in second life? Should I create many triagular prims and link them, or is there a simpler trick?

...and of course, is there a way to move single vertexes just to change its shape? For example, in a regular hexagon move one vertex to the center to create an "empty triangular area" on one side?

SL does not represent solids through their suface. It uses a set of parametric surfaces (prims) that you can link/intersect together.

If you want real polygons you can assemble properly shaped boxes (triangles, squares, etc ...) but if you are trying to build something, my advice is to spend some time playing with the prims and understanding how parameters affects their shape.

Rael

another useful trick is to use a texture that is a picture of a polygon. for example, you can make a soccer ball (polygon) out of lots of little pieces, but it is a lot easier to take a picture of a soccer ball and wrap it around a simple sphere. if the picture has lots of shading and stuff, it ends up looking pretty good.

I understand. So, if I want an hexagon, I have to group togheter six flat prisms...
I hoped there was a simpler way. I understand that working with prims avoids the time consuming approach of meshing, but SL is at least missing a prism with polygonal base, where you can select the number of sides of base.

Yep, it is missing arbitrary extruded n-gons, but you can always make do with triangles (as was noted). In the past, I have written little scripts to create such constuctions with mathematical precission.

Not sure if this would have anything to do with it, but a soccer ball isn't just pentagons. The pattern is a combination of pentagons and hexagons. On a "traditional" ball, the white area would be hexagons and the black "dots" would be pentagons.

But since I have no knowledge of photoshop at all, I don't know whether or not that's the problem you are encountering!

Thanks for the tip; shows you how many times I've seen a soccer ball

The problem is geometry - or tessellations. You can tile a plane with squares, rectangles, triangles or heaxagons. I know you can't with pentagons and am unsure about pentagons and hexagons.

The reason I called it the "orange peel" problem is that you cannot lay an orange peel flat on a table, nor can you take the skin off a globe and lay it flat

One of the reasons SL doesn't support arbitrary n-gon extrusion is that it calculates the sides of the 2d polygon before extrusion based on the current LOD for that object. A sphere may actually get rendered as a hexagon, but it uses logic to make things attempt to resemble the shape they are supposed to resemble. If you could create a 9-sided object, the LOD calculations might turn it in to a 5-sided object instead and it wouldn't look at all like what it's supposed to look like from different viewing distances.

Actually, you can do it with 2 trapezoids. Build a cube, make the height 43.3% of it's width, and set its X or Y taper to 0.5. Copy, rotate 180° on the tapered axis, and align the wide bases together. Voilà.

I know someone in SL that did this already. I was there as he was swearing and aligning...LOL

It wasn't easy, but the finished product was gorgeous. (a geodesic house). IM me in game if you're interested in picking his brain or perhaps he has one that you can use. If I'm not on, I'll answer your IM when I get in.

OK, thank you. I am also interested to understand how to create holes in objects. I would like to avoid to use four rectangular prims to make a square hole in a square... As soon as I am in SL I'll contact you by IM.