First MoI model

 From:  Michael Gibson
3795.2 In reply to 3795.1 
Hi Charles, thanks for the kind words - I'm really glad that you like MoI!

Your model turned out great, it looks like you are off to a great start with MoI!

> Coming from SubD modelling I had to think about my
> approach to the chosen model

Yeah, the overall modeling strategy with NURBS modeling is a lot different than SubD modeling, so that will take a bit of getting used to. But actually these differences are useful because it makes NURBS modeling be a nice companion to SubD modeling since it has a different set of strengths and weaknesses.

Which method you would want to use for a particular project depends on the characteristics of the model. If the model is a man-made manufactured object that is defined by 2D plan drawings, then that's the kind of a thing that fits in really well with NURBS, you can use the 2D curve interaction that NURBS brings to make models like that come together very quickly (and more accurate as well). If your model is much more organic in nature and not really defined very well by 2D profile curves (things like faces, characters, monsters, etc...) then those are the kinds of projects that are a better fit for SubD modeling where you'll be more sort of sculpting the shape by 3D point hull manipulation.

One of the main differences between NURBS and SubD modeling is that Booleans and cutting operations are a primary way of working in NURBS, while they are something that you have to avoid with SubD. So that's a major shift in thinking - in NURBS you usually want to incorporate Boolean operations directly into your modeling approach. This can be a really big shift if you have previously spent a lot of time training yourself to avoid them in SubD.

One area where it is pretty easy to think about Booleans is when you are cutting a hole in an object.

But you can also use Booleans or trimming to carve off pieces of the outside of a shape, not just for making holes - it seems that this aspect of booleans tends to be a harder jump for SubD modelers to think about initially.

Here's an example of this kind of a thing - say you want to make a shape like this:

I've found that a lot of people experienced in SubD will try to initially approach models similar to this by building all the exterior wires of it (trying to define the edgeflow), starting with something like this that they then try to surface:

But with NURBS modeling you don't necessarily want to draw in all the final edges right from the start like that, instead if you recognize that there is a more simple underlying shape that is then cut off, you want to model that underlying shape as a whole more simple piece first, and then draw in some other side profile curves and use them as cutting objects.

Some of the final edges in the model then come from intersections and cuts rather than being drawn in manually.

So the NURBS modeling process for this shape would go more like this sequence:

So that concept of looking for a more simple but extended underlying shape and then cutting that back to get the final model tends to be a major strategy for NURBS that is a bit difficult for SubD modelers to think of at first, particularly when it involves the outside part of a shape - interior holes tend to be easier to recognize as cuts.

Sometimes it helps to think of NURBS modeling as more of a physical manufacturing process where you'll start with some basic pieces of more simple shaped stock, which then have chunks cut out of them (not only holes but also exterior pieces trimmed off) to make the final part.

Hope this helps!

- Michael