boats

[Anonymous]

Yeah Yeah, I know Archicad is fantastic for architecture - I'm hooked, but does anybody out there know how I might be able to use it to create the sort of compound curves you find in yacht & powerboat hulls ??
I'm thinking that I don't really want to learn yet another cad program.


cheers
RSA

[Dwight]

Yes, but not to the resolution you might like.

If you take hull cross sections at small intervals, you can build what LOOKS like a smooth hull in a rendering by using the mesh tool, but the analytic views will always show facets. You CAN hide the interior mesh lines, but this is imperfect. In any event, the only curved edge will be the outer mesh edges - the others will have facets.

The GDL routine to create a smoothly curved surface is called COONS, but there is no interactive tool to create a COONS, and it is not suited to technical accuracy.

Most ArchiCAD objects with smoothly curved surfaces have been derived from models built in other modeling programs.

Of course, we have Maxonform now and it is easy to build these shapes using it.

BTW: while sailboat hulls might have doubly-curved surfaces, most powerboats have single-arcing and flat components forced together using chines and strakes to make a stable hull.

[Anonymous]

RSA,
As Dwight says, it is possible to model a boat hull using the mesh tool.
But, as he says, the resolution is a problem.
I have made several hulls starting with upside down half hulls in AC
using the mesh tool then saved as a GDL object and proceeded to build
a complete object.
The procedure is quite tedious because if you want to hide the ridge lines
and have an approximately smooth shape you have to put in many many
independent points to force Archicad to generate the facets correctly.
The more finely divided the surface is the smoother it is.

Dwight says,
"The GDL routine to create a smoothly curved surface is called COONS"
Unfortunately, this GDL command makes a surface which is also faceted
and you have little control over the details of the shape
because the command uses an internal interpolation algorithm to
shape the resulting surface.

Dwight says,
"BTW: while sailboat hulls might have doubly-curved surfaces,
most powerboats have single-arcing and flat components forced
together using chines and strakes to make a stable hull."

I can't think of an easy way using AC tools to model such a shape
as it involves hard chines formed by the intersection of conic surfaces.
One could possibly do a fair job in GDL using the TUBE command
and the CUTFORM command to make the strakes.

Dwight points out that "Most ArchiCAD objects with smoothly
curved surfaces have been derived from models built in other modeling programs."
I am wondering if any modeling program makes truly
smooth shapes. I have looked at some hull modeling software and
it appears to me that the ones I have seen in fact create a finely divided
wire frame grid "armature" and cover it with a "skin" that is "stretched"
over this armature and forms flat planes across these grid members.
I may, however, be wrong about this.

I am presently investigating Maxonform to see if it is really useful
in making controlled free form objects that are easier to make
and edit than using the mesh tool or GDL.
So far, the people I have talked to have not
had the answers to many of my questions.

Peter Devlin

[Dwight]

There is no such thing as cyber sand and polyester glass filler.

Yet.

[Anonymous]

Or, as far as I know, virtual sandpaper.
Peter Devlin

[Anonymous]

Thanks to all of you for your input. My intention was to get a good approximation of a cabin structure for a boat I have been designing in another software package called 'Hulls' . This product is free and fantastic for multi-chined hulls however it does not produce true perspective renderings and was not intended for the detail of superstructure componentry. Attempting this in archicad was a good way for me to explore the mesh tool as well and turned out to be easier than I thought though I discovered 'Tumblehome'(twisting mesh past vertical) will take some future experimenting. I have attached a jpeg of my boat which is not finessed but good enough for my purpose so you might see my results
- for those interested the hull borrows from american 'lobster' style but with a single chine warped plane hull and is intended for production in stitch & tape plywood

thanks again
RSA

[Anonymous]

RSA,
Using the mesh tool to model a hull with tumblehome is, as far as
I know, not possible.
I had to model a hull up to the inflection point and then
use the GDL command TUBE to model the rest of the hull.
Peter Devlin

[Anonymous]

Peter,
I haven't tried this idea due to time constraint but when i attempted to drag the mesh past the point of 'verticality' (for want of a better word) it basically cut the mesh back to what seemed to be the node points which were nearest to the curve of the hull side panel where the curvature of the hull past vertical. (in elevation this was a line starting half way up the transom angled upward toward the bow until it met deck level)
It seemed to me that you could join another mesh to these remaining node points as long as you initially constructed the mesh with a slope in the opposite direction to the original. Hope that makes sense.
If I get a chance over the next week or so I'll open up the file & have a go

cheers

RSA

[Anonymous]

Guys I urgently need to download a 3d model of a boat. This one from the pic that RSA send is what I am looking for. Can someone please tell me where to find it or can someone send it to me? I looked on many sites on the net but all I'm findind is huge ships that I can't use in my project.

Thank you very much!

[Anonymous]

Guys I urgently need to download a 3d model of a boat. This one from the pic that RSA send is what I am looking for. Can someone please tell me where to find it or can someone send it to me? I looked on many sites on the net but all I'm findind is huge ships that I can't use in my project.

Thank you very much!