Hi Tony, so from what I can see from your screenshot it looks like you're currently trying to construct it by using a 2D curve that is extruded. That method works fine for shapes that are fundamentally straight in one direction, stuff like gears or pipes or things of that nature.

The kind of tapered and curved result that you want is not really suited for using that particular command though - your final shape is not gear-like and does not resemble a cookie-cutter type punched out shape. So probably for your particular case Extrude is not going to be the right approach.

You're probably going to need to use more freeform surface construction commands like Loft and Sweep, and since you are going to be trying to make a kind of seamless sculpted looking type result it's really a quite difficult model that you're attempting to create, pretty much in an advanced surfacing type level of sophistication. You can probably expect to spend many months of practicing and honing techniques before you will be able to actually make it happen. The particular style of model that you're trying to do just tends to be quite difficult, it's not really well defined just by 2d profile curves alone.

So anyway with Loft for example you can create a tapered shape by drawing 2 profiles where one is larger than the other something like this:



Then run Construct > Loft and that will build a tapered object between those 2 profiles like this:


Sweep works by taking one or more profile curves and then a kind of spine-like path curve like this:






You are not likely to be able to construct a final shape like you want there just out of one single command, it has enough variation and kind of branching within it that you are going to need to build it out of separate pieces and then work to try to connect those pieces together. That's an advanced style of NURBS modeling and that's why your project is going to have a high level of difficulty.

Really when you get to a shape like you're trying to do here where it's got a lot of sculpted type blending between different pieces in it, you may be better off using a much different modeling technique called subdivision surface modeling to do that, rather than using a CAD program like MoI to do it.

CAD programs are stronger at building things that are actually defined by 2D blueprints.

Although you can make a 2D silhouette outline of your shape, it is not actually "defined" by that silhouette, any more than just a single silhouette of a person's face captures the entire complex construction of their features.

- Michael