Sub-object editing

 From:  Michael Gibson
2874.3 In reply to 2874.1 
Hi NightCabbage - those kinds of manipulations that you are asking about would be the kind of stuff that you would do in a polygon modeler.

MoI's geometry system is much different than polygons - it uses a system called NURBS solids and one of the side effects of this is that you can't generally just grab any edge that you see and pull it around.

Often times the edges that you see may be "trim edges" and not necessarily the edges of the underlying surfaces.

Please see this FAQ answer which has some illustrations and explanations of how trim curves and "underlying surfaces" work with this geometry system.

Even though this system does not generally allow for pulling edges around, it has other benefits - it's pretty much the reason why booleans work a lot better on NURBS solid modelers than in polygon modelers, because when objects cut one another the underlying surfaces stay the same and only new trim curves are created on them. In a polygon modeler where edges are easily pulled around, when you do booleans it has to fragment things up into a bunch of smaller little surfaces which tends to make things messy for polygon booleans.

So usually if you wanted to make a scaled cube, you would do more of a "construction" way to do it in MoI rather than "squish a different object" method - the construction method is to draw 2 rectangles of the sizes you need and then use Loft between them to build your shape.

That's generally the method that you use for building objects in MoI, you work more on forming and shaping some profile curves, then construct your object from that, rather than taking something like a cube and squishing it around into a different shape which is common in polygon modelers.

MoI's method of "construct from profiles" tends to lend itself very well for man-made objects which tend to be well defined by profile curves. The "squish edges and points around" kind of method of a polygon modeler tends to be good for more organic things like characters, monsters, faces, stuff like that.

So which method you use can depend on what kind of model you're trying to build.

If you're trying to squish things around a lot, then you probably wouldn't use MoI for that, you'd use a polygon modeler instead.

Hope this helps explain some stuff!

- Michael