Hi,
I have a simple box 12 x 3 x 2.5 m
I oriented my faces as it is recommended in the tutorial.
With a 0 trim I give a displacement of 5000 kgf
The results such as draft and LWL (that should be 12 m !) are completely out of range!!
HELP!
You haven’t supplied a model, a version number of Orca3D, or what the results it reports are.
I don’t have a copy, but as a reality check two of your first steps could be:
- check vs Rhino3D’s built in hydrostatics command vs the draft you think it floats at (or really, any draft if LWL is coming out odd for a box at zero trim)
- cut the box off and look at volume and center.
You specifically mention orientation of the faces. Is it a pRhino3D solid? A few faces that happen to be sitting next to each other?
Where is the box located and how is it oriented? Does the reported LWL, which is another thing you haven’t told us, make sense if Orca3D thinks the vessel is sideways? A sideways catamaran symmetric about centerline? Etc.
What did you enter for the center of gravity? If the LCG is not in the center of the box (for example, it’s at one end), you will get unexpected results. If that doesn’t resolve it, please send the model to support@orca3d.com and we’ll have a look at it.
Nathan brings up a good point about the orientation. Orca3D doesn’t enforce an orientation (for example, the longitudinal axis can be X, Y, or Z, and the forward direction may be positive or negative). But you have to define what orientation you are using, in the Orca3D Properties panel. Then when you enter an LCG, TCG, and VCG, Orca3D knows how to interpret that, and values such as LWL will be correctly reported.
I read more carefully and realize that you entered 0 trim (and presumably 0 heel), in addition to the weight of 5000 kgf. This is what I see in that case (depending on your version of Orca3D the report will look slightly different):
Hi Michel, It looks as if one side of the box is missing. If this is meant to be half of the hull, then that open side should be at Y=0.
Thanks to all for your responsive and useful responses.
My problem was created by the fact I had not positioned the LCG.
Thanks again.