Problems with creating an offset file with autoship

Hello everybody,

I'm a student at Chalmers, Sweden and doing my master thesis with Shipfow, a CFD program for ships. To run the CFD code I need an offset file of the hull. I use autoship and autohydro to generate this offset file. I have some small problems and don't know how to solve them. (because I'm not very familiar with these programs) I do the following steps to generate the offset file:

1 import the iges file into autoship

2 add some stations

3 create a group of the hull surface with stations

4 export this group to autohydro

After these steps I do some minor changes to the export file so I can use it as input for the CFD code. The problem I have is the following: There are a number of points on every station. The first point is on the centerline of the ship at deck level. The second point is on the centerline at the hull. The next points follow the hull until deck level. The last point is on the centerline at the hull again. (see attached image) Does somebody know how to create an export file without the first and last point?

Koen

 

Koen
In AutoShip, it is easiest to take the model as it stands, import it to "modelmaker" (part of the AutoShip suite) and remove the excess points there.
This is something that I have never been able to figure out how to do without the extra step, but it is not difficult to do with modelmaker.
Are you there, Russ?

Steve

 

You might also make a group of a group, before exporting to modelmaker, this tends to be cleaner, without the wayward points. i.e. make a group of your desired surfaces, call it group 1, then hide the surfaces, leaving group 1 on its own, select this group and use this to create a new group 2.

You could then mirror this group to port and starboard before exporting to modelmaker.

Make sure that all surfaces are joined or trimmed before making the group.

In modelmaker there is a button to remove excess points. You may have to do some fine tuning manually.

Another approach is to make separate gf files for the hull and appendages, but I don't know how this will work for the CFD

Hope this helps.

David