Making sense of Zebra View in SolidWorks

[AON]

I had created the attached as a guide to interpret the Zebra View of my Hull and offer it here for others ( hoping it has some value as I have yet to "get it" .....but haven't given up yet!)

 

I include a Zebra View image of my hull.

if anyone understands Zebra View and can offer some insight it would be greatly appreciated.

 

Alan

TRYING TO MAKING SENSE OF THE ZEBRA VIEW IN SOLIDWORKS.pdf

[Don9of11]

Hey Alan, I think from watching this short video http://www.youtube.com/watch?v=32E_iLzXeJk  the zebra stripes should all line up, there shouldn't be any breaks in them. If it were me, I would visit the SW forums and ask those folks what the lines mean in the context of a ship hull. Something else I found that might be helpful http://blog.capinc.com/2011/06/solidworks-tech-tip-how-smooth-is-smooth/

 

The shape of the hull is complex and double curved (ie spherical) in nature, especially at the bow. You might want to experiment by making a ellipsoid or other football shape where you know the lines are true and study the zebra effect on those instead of using rectangles and cylinders. (IMHO)

 

I'm going to look back through my SW 2004, I saw some references on the SW forums that indicate my version might have the Zebra feature.

Edited May 6, 2014 by Don9of11

[AON]

Thank you Don

 

I'll watch the video tonight when I get home.

 

Alan

[Don9of11]

Alan it turns out I do have Zebra line feature. Here is an image of my ship lines

 

 

 

The top view is with the spherical option and the bottom view is with the cube option. It is very confusing to look at and I haven't figured out exactly what its showing me.

 

 

[AON]

Believe me - I know exactly how you feel!

 

isn't technology wonderful... we now worry about the tiniest dimensions and now stripes when are grandfathers would have just made it work even if it took a good wack or two with the 10 lb pursuader

Edited May 7, 2014 by AON

[jud]

Is that a representation of the difference in elevation similar with contour lines, the reference plane being C/L with that plane being horizontal in both ways. Never have seen anything quite like this, it just looks like a way to graphically show the rate of change along the hull, Anyone have a definition of what a "Zebra View image" is? The Z component of a XYZ coordinate?

jud

Edited May 7, 2014 by jud

[AON]

Zebra View is a mirror reflection of lines on your shape ... your shape is the mirror

as the shape changes the reflection of the lines adjust

it highlights changes in shape, mates and alignment

 

I am still having trouble wrapping my head around what it is telling me.

a perfectly fluid shape would, I believe, have long lines reflected... their direction might change but not sharply and they would change as a group

[Don9of11]

If I understand Zebra lines, they represent the smoothness of a surface. In the top view, my ship the lines are all contiguous until you get to the dead flat and just forward of that the zebra line gets smudged out. The same is true for the bottom view. This indicates there is a problem, a dent or some other deviation. The same thing can be seen in the aft part of the ship near the keel and other areas if you pay close attention.  Wherever the zebra lines break or fail to merge together smoothly there is some kind of deviation in the hull and in fact by measuring various points along the waterlines (not shown here) I do indeed have issues with the frames just forward of the dead flat and probably in other areas as well.

 

As with anything you see for the first time, its difficult to determine the significance of the zebra lines without a comparison to a goodly faired hull. If one could scan the hull of a real ship or even an admiralty model we might be surprised at the results. For all I know the pattern of these lines might be acceptable at the scales we build our ships.

Edited May 7, 2014 by Don9of11

[Don9of11]

Here is an example of a Bounty class launch that has a perfectly shaped elliptical hull. In the real world you would never see this, at least I don't think you would. I would think you would see symmetry on the view of the bottom hull but that must depend on the position of the cube and the mirrored surface of the boat. The lines do flow all together so this hull is smooth. 

 

I think this could be a good visual tool to easily see bad spots in a hull but ultimately its going to be the traditional measurement of waterlines, buttock lines, etc. that determine the fairness of the hull.

 

 

 

 

[jerry_bee]

Zebra shading allows to determine the smoothness of a hull. The more strips are parallel, the flatter surface along them. The higher density of strips, the higher degree of the hull's curvature.