Parts Is Parts - Right?

[thanosnaranja]

This is a question about general organization of aircraft parts. I'm familiar with the required organizational hirearchy labelling system needed to pass a model through makemdl.exe What I'm wondering about is this:
In many of the tutorials I've read the authors are "welding" everthing together. i.e. They they design and physically (virtually) attach a vertical stabilizer to the aft fuselage; weld the two pieces together and so on with other parts of the aircraft wings to fuselage, engine nacelles to wings, etc. etc.
(This may be a stupid question)

So my question is - is this necessary? If all the parts are linked to each other through their hierarchy won't the sim put all the pieces where they belong? I mean I have all the pieces correctly located with respect to one another, but I have not bothered to weld them all together by joining vertices as though I were building a real plane.
For instance, I have here a control shaft inserted into the working surface of a canard which will extend through the skin of the model and the canard will rotate about it. Does the shaft have to be attached to the canard by welding vertices together?

http://www.flightsim.com/vbfs/Attachments/up1/98626.jpg

Comments please.

[EngEd]

Hello,
As I often mention about Gmax, it (and I suspect FSDS) allows a lot of choices in technique, etc. Some may prefer to collect objects and weld them. Others prefer otherwise.
I tend to keep major elements separate rather than combine them. I find them easier to texture this way. A tradeoff is a lengthy list of objects.
But, as you say, Parts is Parts. As long as hierarchies and animation linkages are correct, it doesn't matter in the final product (unlike in the real world...).
On the other hand, I'd likely Attach that shaft to the canard as they're going to rotate together, right? Once attached, I'd do a general weld of the resulting part (set at 0.01 unit) to collapse coincident vertices.
Regards.
Dennis S

[andyjohnston]

Even the hierarchy isn't required. You could leave all the parts separate and the plane will still work, as long as none of the parts rely on the movements of others.

[n4gix]

>Even the hierarchy isn't required. You could leave all the
>parts separate and the plane will still work, as long as none
>of the parts rely on the movements of others.

That is not completely accurate. Some form of hierarchy is required with both GMax and FSDS3, or any other program that uses MakeMDL.exe to compile the model. The bare minimum is "exterior" and "interior" ;)

I use hierarchy a LOT, because it makes working on major assemblies so much easier.

All the parts associated with a glareshield/panel for example are "Linked" to the root part. The windows, levers, hydraulic pistons, and accy's for each door are all "Linked" to their respective doors, etc.

About the only time I "weld" parts such as a vert stab to the fuselage would be to smooth the transitions... Sometimes it is necessary to prevent "shimmers" at the intersection of two parts...

[dzignguy]

I agree with Bill's comment on hierarchy and also must say that all these parts add measurably to the memory load of the model once compiled. A good test would be to build an airframe with separate parts just as the original poster talks about. Compile that model and see what the memory load of that model in the Sim is.

Now, build that same airframe as one or as few cohesive Parts as possible. You must always have some parts / assemblies that are separate but I think you get the idea here. Not only will you end up with less memory load your polygon load will usually be less also. To say that texturing each separate part in a multi part assembly is easier than a Multi-Sub-Object Material, UVW unwrap of a large, cohesive part is just not true. Yes the concept initially may be a little harder to learn but once understood, far easier than the separate method commonly used.

I would not expect a beginner, or low experience user to understand all of these methods. However, it should be something that is talked about and pointed to as a goal for intermediate modeling skills. I can commonly cut 30-50% of the polygons from a multiple part airframe by simply joining them and refining their structure to take advantage of smoothing and smoothing groups. It is actually easier to map and texture such a model as the “blends” between textures work better in the MSO material and UVW unwrap system. Check the “high end” work of the artists / modelers on some of the 3DG forums and you will see that this is common practice.

My two cents. :-)

John

http://fsdzigns.com/images/jhwLogo_00.jpg