For instance, I have the waterline of a hull at 0 on the Z axis with the entire hull in the negative Z direction and the Hydrostatic command fails with 2 bogus results-wet area, and volume(I think). The command does not report fully until I move the hull significantly in the positive Z dir. which is useless because its not doing calculations above 0 of the Z axis.
Also the hull is orientated along the X axis (longitudinally) while the beam is centered on the Y axis, despite this it reports that the Center of Buoyancy is outside of the hull area for the Y axis. I believe this is physically impossible unless the hull is made of lead and has a hole in it.
And if I remember correctly in ver.4 the axis’ for Center of Buoyancy and/or Center of Floatation was reporting in the format X,Z,Y not X,Y,Z as it should. Has this been fixed?
The reported coordinates for CoB and CoF are in the gazillionth of an inch in scientific notation, why doesn’t it obey standard unit tolerances?
Lastly You put spaces in the reported coordinates making copy/paste useless for things like setting a point to mark these important spots, why do You go against Your own conventions…
For instance, I have the waterline of a hull at 0 on the Z axis with the entire hull in the negative Z direction and the Hydrostatic command fails with 2 bogus results-wet area, and volume(I think). The command does not report fully until I move the hull significantly in the positive Z dir. which is useless because its not doing calculations above 0 of the Z axis.
If there is a naked edge below the waterline (other than exactly on the mirror plane for Symmetric=Yes) then only wetted surface area and waterplane area are reported. Check to make sure the top edge of your hull is exactly at or above zero everywhere., or extend it slightly above the waterline. Also make sure no naked edges, no matter how small below the waterline.
Also the hull is orientated along the X axis (longitudinally) while the beam is centered on the Y axis, despite this it reports that the Center of Buoyancy is outside of the hull area for the Y axis. I believe this is physically impossible unless the hull is made of lead and has a hole in it.
And if I remember correctly in ver.4 the axis’ for Center of Buoyancy and/or Center of Floatation was reporting in the format X,Z,Y not X,Y,Z as it should. Has this been fixed?
I’ve never had a problem with the CoB being outside the hull. CoB and CoF are reported as X, Y, Z values in World coordinates in V5. My recollection is they were reported that way in V4 also.
Naked edges will screw things up. I use ORCA and often compare its hydro against the Rhino native output, If you are using Rhino Hydro, be very careful about naked edges above the zero plan which is where Rhino will want to place the waterplane unless you tell it otherwise. It is usually very much in agreement with the ORCA output as long as you haven’t screwed somthing up. I’m not being critical, it is just easy to get some parameter wrong in hydro and get wacked results!
Thank You Everybody! I took into consideration everyone’s reply. It does seem that naked edges are problematic to this command (hmm NO mention in the help file)
Using 1/4 of a hull to run hydrostatics on seems to be unreliable for me, and mirroring then joining has problems too. What does appear to work is mirroring the 1/4 hull
and running the "Join 2 Naked Edges " command on the seem at the Keel of the vessel.
But still these issues:
The reported coordinates for CoB and CoF are in the gazillionth of an inch
in scientific notation, why doesn’t it obey standard unit tolerances?
Lastly You put spaces in the reported coordinates making copy/paste
useless for things like setting a point to mark these important spots,
why do You go against Your own conventions…
Could We (by “We” I mean McNeel ) put a function in this command to set colored cross hairs or points to mark CoB and CoF. Just a thought…
“1/4 hull” - Do you mean one half of a symmetric hull?
Using one half of a symmetric hull works reliably provided the center edge of the hull is exactly on the y=0 plane. SetPt can be very helpful to make sure the applicable control points are on the plane.
From the Help file:
Notes
To get displacement information there must be no naked edges below the waterline except in the case of Symmetry =
Yes, in which case there can be naked edges on the symmetry plane.
If the waterline falls on a singularity (place in the surface where points converge like at a pole of a sphere), the command will fail. Move the singularity point a fraction away from the water line.
@David, Yes of course 1/2 of the hull-1/4 of the vessel. I’m making a watertight (lol i hope!) closed catamaran type hull so I think of the 1/2 of hull as a 1/4 of the whole vessel.
Good God! I don’t know how I over looked that in the help file–didn’t scroll down enough maybe—Jeez! the old gray matter aint what she used to be
I’m going to check My center edge now…Thanks for Your time, Carl
) put a function in this command to set colored cross hairs or points to mark CoB and CoF. Just a thought…