Hi Kevin, it would probably help quite a lot if you could post some pictures over in that thread (especially close-ups of the canopy) of the real shape.

Otherwise it is just hard for me to understand exactly what you mean by "flatness" or make it look right from the front, etc...

It sounds a bit like you may want to focus more on adjusting the shape of that centerline scaling rail curve to fine tune the shape that is generated.

Definitely though just drawing contours of irregular topology and trying to surface directly to all of them as exact edges of sweeps or networks usually does not tend to give the best results.

- Michael

Michael

I've posted the wingtip problem here http://moi3d.com/forum/messages.php?webtag=MOI&msg=1762.1

Like I said, I almost get what I want with Nurbs and if I could point tweak I could probably fix it.

However, I might have modelled the wing in a bad way so am open to suggestions on how it would be best to tackle this part ?

Hi Michael

This was the other issue I was talking about with nurbs where tensions get created in the nurbs surfaces warping it from the shape you want. Having the ability to tweak points would allow the user to fix this.

Today, aircraft are designed with NURBS. Fantasy aircraft and unrealistic objects are modeled by Poly and SubD.

If this aircraft were being modeled TODAY, it would be done with NURBS.

I'm sure it would but I still can't get the shapes I want as you can see from my last post.

Hi Kevin,

> This was the other issue I was talking about with nurbs where
> tensions get created in the nurbs surfaces warping it from the
> shape you want.

Yeah this kind of thing will tend to happen if you try to build a single surface that goes through significant changes.

One thing that could help in this situation is to separate this out into smaller pieces - one piece for the main fuselage that goes more evenly towards the back and then have the tail fin as a totally separate part that then gets booleaned or trimmed to mate with the main fuselage and then a fillet or blend put in between them to make a smooth juncture.

Trying to make a large protrusion as a single surface construction will be much harder to control than building in smaller pieces.

The kind of tensions that you are showing here are basically the result of one profile transforming into another one, probably you don't like the default mapping or connections that are being used between each profile. You can get some more control over how the profiles connect to one another by using Network and putting in some more section curves, that can let you kind of control the connections some more.

But really I would think building in more simple pieces, one for the main body and the tail fin as a separate piece would be more of how I would go.


> Having the ability to tweak points would allow the user to fix this.

The ability is actually there - you can select the surface in your example there and use Edit/Show pts to turn on control points. Then you can select a point and move it around to deform the surface. But in MoI this does not tend to be a very big focus of the toolset. If you want to model by tweaking the surface mesh points more directly probably you should be using a subd modeling tool instead.

- Michael

>But really I would think building in more simple pieces, one for the main body and the tail fin as a separate piece would be more of how I would go.

Yep, it seems it is the only way (pretty much like the real aircraft in fact). I try to avoid doing this though because it is much harder to sent up geometry wise and you tend to end up with meshing flaws once exported to a polymodeller. Even though meshing in MoI is far better than Rhino it still has its problems at joints and I really want a nice smooth clean mesh.

Hi Kevin - re: nice smooth mesh - if the problems you are seeing is a lack of smoothness when importing into Max 9 in particular, that may be greatly helped out by getting the updated FBX import plug-in.

If all goes well, that should enable you to get the accurate surface normals transferred over and have those used for shading the mesh in Max.

When you get the accurate vertex normals it really makes for a much smoother shading and it can pretty much eliminate the worrying about how the mesh is specifically arranged.

This has been a big problem specifically with Max because unlike other programs it does not seem to like to read this information out of other formats such as OBJ format.

The main reason why I wanted to do the FBX export was to hopefully get rid of this exact problem.

- Michael

>if the problems you are seeing is a lack of smoothness when importing into Max 9 in particular,
> that may be greatly helped out by >getting the updated FBX import plug-in.

That is fantastic news as that is the main reason I gave up on Rhino in the past was inability to create a decent mesh from all the surfaces.

I've downloaded the latest FBX plugin for Max 9 so, I'll give it a go and let you know if it gives better results.

PS Max seems to import OBJ format just fine. The messy mesh joints occur in MoI and Rhino. Both programs have trouble stitching the mesh together at the nurb surface joints. The problem is much less in MoI compared to Rhino.

Hi Kevin, well if the joints do not look right in MoI then the FBX export is not going to help with that particular problem.

If you have an example of that it could help if I could see it.

But my guess would be that you had an export where you had 2 surfaces that were separate objects that were sitting next to each other, rather than having them joined together to be a single connected object.

You need to join surfaces together to have shared edges before you export - if you don't they get meshed individually without any awareness of each other and they can get slightly different vertex structures along their adjacent edges, creating small gaps or cracks.

When they are joined together to be part of one larger object that has shared edges, the edges will be treated with special attention to have a fully compatible vertex structure along the shared edges, so no cracks or gaps will happen there.

So be sure to use Edit/Join to glue surfaces together to have shared edges before you export and that will solve that problem, if that is what you were seeing. That applies to Rhino and MoI both actually.


> PS Max seems to import OBJ format just fine.

Sort of - I mean it brings the polygons over but did not seem to bring the vertex normals over, so it calculated shading by averaging polygon normals together instead of using the true normals that come from the original NURBS surfaces. When shading is done with the true normals it eliminates a lot of shading artifacts and gives a much smoother appearance.

- Michael