I need some help from the Moi pros here... what's the best way to model this (R/C car body)? Doesn't have to be very accurate, close will work. I've got some ideas, just want to learn about different approaches being new to NURBS and 3D in general. Thanks!

Hi lee - some of the easiest ways to start are to first try to divide your object into a couple of different logical components, and then start to sketch some of the profile curves for those components.

So for example with your shape one good division would be to try and handle the canopy type area and the body as 2 separate shapes and focus only on modeling just one of those at a time.

So if you just ignore the canopy/cockpit part of the shape for a moment, you could sketch an outline of the body something like this in the top view:



It is easiest to draw just half of that shape and then use the Transform/Mirror command to make a mirrored duplicate. Make sure the endpoints of the half that you draw are snapped directly on to the axis line so that the mirrored result will be symmetrical about that axis line.

Then go to one of the side views and sketch this additional profile:



These are how they are arranged in relation to one another in 3D:



Now select the top-view profile, and run Construct / Extrude to punch it out into a solid, like this:



Now you can select that solid, and run Construct / Boolean / Difference to cut it with the other profile:



This has now divided the solid into 2 pieces, you can select and delete the top piece.

Then it is possible to select these edges:



And run the Construct / Fillet command to round them off so they aren't quite so severe:



That's one of the easiest approaches to building a shape - doing it only by 2d profiles like this will tend to make a somewhat blocky result, but that actually fits pretty well with your shape in this case.

Then to do the cockpit part, one idea would be to draw a top and side profile for that, and then use the Construct / Revolve / Rail revolve command - it can build a kind of revolved dome type shape that matches a profile curve.

Hopefully the above will give you a method to get started though, let me know if you get stuck on any part or if you need more help building the second part after you have made some progress on the body.

Definitely try to break things down into pieces though, it is easier to get started when you focus on a more simple piece of a model at a time.

- Michael

Thanks Michael! Why does my mesh have the extra edges? Also it will not let me fillet any more than this... thanks again.

Hi lee - that's because your base curve that you are extruding is made up of many segments.

Each segment in the original curve will extrude up into a different surface that is joined with the neighbor surfaces.

If you want to reduce the number of edges, you'll need to fuse together those many-segments into single larger segments. One way of doing that is to turn on control points and delete the control point between 2 segments - that fuses them into one segment.

The one that I drew did not have so many pieces because I drew the outline as one longer curve using the Freeform curve command. That made mine just one segment (or well 2 after mirroring).


re: can't fillet more than this - the maximum amount of fillet can be limited by tight curves in your shapes, but I don't see anything really too tight in your screenshot there.

If you can upload your .3dm model file before filleting, I can take a look at it to try and see why you can't fillet any larger than that.

- Michael

Here's the 3dm. also a couple renders of the radio model you helped me fillet, my first moi build.

Hi lee, the radio renders turned out great!

The fillet limitation is a bug in the v1 fillet mechanism - this is improved in v2, in the current v2 beta you can go up quite a bit larger, up to 0.7 units.

Your front profile is a bit lumpy:





Those kinds of lumps and bumps tend to make things harder on the filleter - you may be able to get better fillet results if you make your cutting curve a bit more evenly smooth shaped instead of with that lump in it.

- Michael

Just curious.

With the x-ray 3dm file in MoI V2.

When filleting the top edge up to 0.4 was fine, then, when I tried 0.5. the side panel dissapeared?

Brian

Hi Brian, - strange, over here I don't seem to have any problem with radius 0.5 ...

Can you check to make sure you're running the Aug-4 beta and not the Aug-1 version?

- Michael

Michael
2.0.2008.804 Aug 4th?

Brian

And I just repeated the exercise.
File attached.
Brian

@brian
http://moi3d.com/beta.htm

I bought a license and downloaded V2, well worth it. Also messing around with lofting, I mirrored one side so I just fine tune control points on one side.

Pilou
Yes, thats what I am using.
Brian

Update...

The fillet was made from the faces again, I could not get the edge fillet to work.

Hi lee, looks like it is taking shape well there!

Yeah edge fillets can still be rather finicky even with the other improvements that are in v2. It is unfortunately by its nature a difficult area of calculation.

Another thing that can make it fail are areas where 2 edges come together and are very nearly smooth with one another but not quite, like for example a 3 or 4 degree angle difference where the edges meet up.

That makes it try to build a corner connecting piece there and with a small deviation it will be a very tiny corner, those kinds of tiny pieces make things difficult.

The face/face filleter on the other hand does not try to build corner pieces.


Thanks very much for your order, and it definitely looks like you are making great progress there.

- Michael

Thanks! I've learned a lot the past couple weeks using Moi, great software.

here's an update and render of the body: