Hi Scott - making shapes in a separate "patch by patch" method like that will tend to naturally result in shapes that have creases where they meet up. That happens because your shapes basically stop abruptly at their ending spot.

Usually to get smooth surfaces you need to instead build things in large broader pieces rather than as doing them as separate pieces.

See here for some more explanation of how building a shape that "stops" at a boundary will result in creases:

http://moi3d.com/forum/index.php?webtag=MOI&msg=1398.18
http://moi3d.com/forum/index.php?webtag=MOI&msg=1398.19

Notice how in Burr's previous example above, the 2 separate forms for each broad shape is not made up of fragmented bits but instead one big single surface?


> even after running the Join command.

There is a major difference from how Joining works in NURBS modeling as compared to polygon modeling.

In NURBS modeling joining makes a connection between pieces but it's purely a topological connection where the system now knows how the outer skin of a solid is connected together - nothing changes in the actual geometric shape of surfaces when they are joined.

Also in a polygon modeler even if you are not doing sub-d smoothing you can merge polygons together and then they get the sort of fake smooth phong/gouraud shading applied to them to make the rendered result look like it's smooth even though it's really made up of flat polygons. That's also very different from NURBS modeling - NURBS modeling doesn't use any kind of fake shading to it at all, things will only be smooth if the surfaces that you have constructed actually are smooth to one another.


Basically with NURBS modeling you don't really want to be building things in a patch-by-patch manner like that - instead for things that are supposed to be smooth build them out of a larger single surface, and when there is a transition between broad shaped forms, don't try to build that transition directly into your surfaces, instead focus on building each broad form separately and then they will get trimmed or booleaned where they cut each other and have a transition constructed using fillet or blend.

- Michael

Hi Scott, just a few more notes on what you asked:

> Blending the edges didn't work.

Blend creates a new surface in the empty space between some edge curves. In your case you've got all the pieces touching with no empty space between them, so there's no room available for a blend surface to be created, that's why it would not do anything for you.

See here for some examples on how you would have things set up for doing a blend:
http://moi3d.com/2.0/docs/moi_command_reference7.htm#blend


> Trying a Boolean didn't work wither.

Booleans only intersect objects with one another to cut away parts. Similar to Join, Booleans will not alter the geometric shape of a surface, they will only alter trimming boundaries to cut away some more areas of surfaces.


Like I mentioned previously, really this kind of project with semi-organic type forms does not tend to leverage the best strengths of NURBS modeling - if you're already comfortable doing sub-d modeling then doing things that are more sculptured in shape and semi-blobby-ish without much 2D profiles to them will tend to be better done in your sub-d modeling program.

Models that have more 2D design elements from them and things like holes and cut away areas will be the kind of stuff where NURBS modeling becomes much more useful for you probably. The particular model that you've targeted here is not in that kind of category though.

- Michael

BurrMan

I do like what you have done here with just these two curves.
Yes, could you please describe what you did?

Scott

Hi Scott,
Here's a video of how I made the example.

http://youtu.be/LtElXqa6dDM

In the video, I talked about a poor decision in my model to create a "radiused curve" in the originating curve, instead of a hard edge.. This can create problems later.

I tried to make note of showing how the red curves from your original model are trying to mimic what the fillet creates. Trying to hand model those would be hard. I suppose the trick is to figure out what the original shapes and orientations are that would have the fillet edges match a "picture" or somthing...

I also think that if you are trying to "totally match" from a picture, you may get better results by using a revolove, instead of the blend i use, on the initial pod shape.. Revolving half of that curve, then turning on control points will allow you to change the shape in a way to match your base curves you started with...

BurrMan,

After trying many different beginning shapes and tools, I finally went with your suggestion and started with a basic ellipse shape.


Then, I created a bulge via the blend tool, mirrored it and shaped it.


Next I created 3 ellipses that matched the shape of the upper section.


I then did a loft through those three curves.


From there, it was easy to merge those two pieces together.


Then came the small camera in the front. I did have a small issue with creating a fillet and had to do it manually. Thanks Jason.


This was all part of a model of LUNA, a German UAV that I'm building for one of our customers.


Thanks for all your help.

Scott