Tote-ally frustrating!

[Steve Maskery]

HI all,

Can anyone explain this to me?
I've designed this 'ere tote for my Veritas model:

I drew the fore and aft backbones, then a semicircle, and did Follow Me on the semi-circles up the spines. With me so far? Good.

The result is OK, not perfectly like the real thing, but close enough for jazz. What I don't understand is why there is no side surface when I join the top corners and the bottom corners - the arrows in the drawing.

If an arc is being dragged up the spines, surely the arc ends will be on the same surface, and closing them off top and bottom should produce a face?

The face on the far side has been generated manually, which is not too onerous, but it's not the point. I don't understand why it appears not to be planar.

Is my logic at fault or what?

If anyone wants to play, go to the 3D Warehouse and search for half-a-tote.

Cheers
Steve

 

[Nick W]

Steve,

Is it another one of these problems where if you scale things up by 10 it all works OK? You can then scale it back again b.t.w.

There must be some problem with the coding if SU can't cope with these rounding error problems - they do seem to be rather too common.

 

[SketchUp Guru]

I think a big part of it had to do with the size. Take a look and see what you think.
http://sketchup.google.com/3dwarehouse/ ... c5253bb7e1

 

[Steve Maskery]

Hi Dave,
That's fine - so what did yo do differently? Just scale it up and back down again?

BTW, mine was giving errors "SU can fix it" Yeah, right. Half of it disappeared - that's right, the sides I'd put in.

At least I can move on now.

How's everyone else's coming along? Are you doing this one too Mike? Surely it's not just me with too much time on his hands?

Ah.

Cheers and thanks very much
Steve

 

[SketchUp Guru]

Steve, probably the main thing I did was scale up by a factor of 10. I also ran Intersect with model and drew in a couple of additions to the planes on the top and bottom. I also deleted some unneeded surfaces on the insides and then stitched in to fill the faces on the side. Then I softened all the lines and added the texture.

I'm thinking that although it seems those edges should be coplanar they aren't which is why the triangulation must be done. I suppose there could be some small degree of difference between the two due to the Follow Me operations.

Edit to add: Notice at the bottom right arrow in your JPG that the line of the plane at the bottom disappears under the edge of the front profile. I think that's a pretty good sign things don't remain coplanar.

 

[Steve Maskery]

Notice at the bottom right arrow in your JPG that the line of the plane at the bottom disappears under the edge of the front profile. I think that's a pretty good sign things don't remain coplanar.

Hi Dave,

Yes, but that is because the arc ends are not intersecting that plane there, they are lower. so that bottom horizontal plane intersects those particular arcs closer to the centre.My logic is that the arc ends, which is what I am trying to join, are all one radius distance away from the backbone, and should therefore all lie in the same vertical plane (assuming that the backbones are both in the same plane, which they are).

Clearly everything is not planar, but I don't understand why not.

Cheers
Steve

 

[SketchUp Guru]

Such hard questions so early in the morning! It isn't even 6:00 yet.

When I get in to work this morning I'll try another look at it. I don't know all the reasons why SU doesn't fill in faces. It does most of the time. I've got an idea that it is still related to the front lower corner. We'll see.

 

[Nick W]

Steve,

My money is on the straight line segments with which the curves are approximated, not being in exactly the same plane. Have you tried zooming in really close to get a butcher's?