[jrmach]

Trying to draw a convex ellipse.Can't figure this out.Kind of want it like a ford emblem.No,I am not making a Ford emblem.A customer likes the shape and he wants to put a 3d engrave on it.So I need a solid to project to.

[BurrMan]

Used revolve on the 2d curves. Boolean diff the block from the revolve.

[jrmach]

Thanks,thats it.For some reason this particular shape was playing like illussions with me,ha.

[jrmach]

Now does anybody know how to figure out what size of ellipsoid to start out with so that when I slice the top off,that it ends up with the right height?

[BurrMan]

Use 3 points. Have the 2 outside ones lower that represent the width and one in the center for the height and draw your revolve spline going through those. cutter goes at the 2 lower points level

[jrmach]

Having no sucess here.:withstupi
FWIW,in V25 you draw an ellipse and if you go to edit to undo,they call it a rectangle.

[aldepoalo]

jrmach

you could always use bobart for something like this, you did say you were doing a logo?

[jrmach]

I need to project a 2D drawing for engraving on surface

[jrmach]

Here is a wireframe of what I am doing.Can someone show me how to make as a solid please??:drowning:

[jrmach]

OK,I did it.Broke the model in 4 pieces and did a 3 edge surface on each one.Then I Boolean the 4 surfaces together.And thats exactly what I was looking for.But there has to be a better way,no????:banana::banana::banana:

[aldepoalo]

Jr machine this is easy to surface!

1) Break many

Break all the geometry where it intersects.

2) Only work on 1 quadrant of the ellipse and do a 3 edge surface




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3) Now that you have your surface just mirror for the other 3 sides and your done!



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[jrmach]

Yeah Al thats another way.I am still at a lost to Burrs way.I still have more work to do on engraving,painfully slow,but the base is almost done except a radius border.Nothin like a 5 or 6 hour project to keep me out of mischief.Here is a sneak preview,this is not my idea,I am just the artist,modeler,engineer,machinist,etc.

[BurrMan]

Jr machine this is easy to surface!

1) Break many

Break all the geometry where it intersects.

2) Only work on 1 quadrant of the ellipse and do a 3 edge surface


3) Now that you have your surface just mirror for the other 3 sides and your done!

Can you show that this creates a smooth contiguous surface (not)? I agree BobArt can do it quickly.

The big addition that can help with these types of surfaces is "scale 1d" when precise dimensions are needed. But he can do it withthe revolve also, it's just not "easy".

[aldepoalo]

I didn't try the revolved, so I'll have to try that... I was also thinking a skin, 4 edge and even a sweep for a shape like this.

In the past I would create a surface for the curve then extrude the profile and add, then un stitch and delete what you do want.

I also agree where the edges are on this surface because it's mirrored could be an issue...

[jrmach]

I screwd with the BobART and wasn't getting the results I expected so after so much time spent in that direction I shifted gears to drawing the wire frame and 3 edges which worked,albeit as you pointed out a little bit of edge problemo.There was another approach which I have not tried yet and that is from the wire frame model I can get the radius's and from there draw a torus and slice the top off that.That would be clean surface,yes/no?I havn't thought that out all the way though,but any way that's all I got.If a guy could revolve that would be the best but all my efforts were unsuccessful. What do you mean scaling in 1d?????????

[aldepoalo]

jrmach,

Using the revolve is not as hard as you think. You have all the wire frame that you need!

1) Snap a point to the arc center of the long arc. We are going to use this as the axis of rotation. So snap a point to the long arc center, then draw an incremental point like 5" in y and then join a line between the 2 points.

It should look like this when you are done.


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2) Now that you have a line to pick for the axis of rotation, you are ready to revolve.


It should look like this when you are done.


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3) From here you can project your art work, and even cut the shape using the ellipse as a boundary. IMHO I could cut the shape to the profile of the ellipse. Do do so I may need to extend the short arc so that it's past the ellipse on both sides before I do the revolve.

Either way when done it would look like this


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* If don't want the "edge" in the center just rotate the revolved surface prior to cutting the ellipse back...

jrmach I hope that helps you understand the revolved method a little better and burr this method is a lot easier than the 4 edge surface layout I've done in the past.

[BurrMan]

burr this method is a lot easier than the 4 edge surface layout I've done in the past.

I've worked this shape in the past with 4 edges and skinning and it becomes complex for me. The surfacing commands would really need a means to interact with other surface edges and maintain uv tangency. If you cant get the shape in a single skin (With this one I dont think you can) then no go. You would have to use the trick of putting a "small planar ellipses" at the top.

The revolve gets it. (The extensions past any trim boundries would be preferred)

[BurrMan]

What do you mean scaling in 1d?????????

Scaling in 1d is the ability to choose a scale direction, lets say "Z", and scale the object down in "-Z" with only the top of the object scaling down, the bottom would stay put.

Here is a file with a sphere cut in half at 0,0,0.

Scaled in Z 1d down, then scaled in Y 1d down, then scaled in Z 1d down again...

Get it?

[jrmach]

FWIW,the Taurus way works too,BUT there seems to be issues along the edges,my guess a tolerencing or arc segment scandal of some kind.Soo,strike that as feasable.But really the 3 edge looks pretty good from whhat I see,will know in a few days when I run it.
Al.no big deal,but an ellipse is not a rectangle as it says if you go to undo the operation.Does it in 25,not 23.Not nit picking.Thanks for all help Burr and Al.Always many of ways to skin that cat.Bob may not be the best to draw in,but as Burr consistently points out,it can be done with Bob.Attached is lousy outcome of torus way.It works,just not very good.Learn,learn,learn,ughhh!

[dwood]

JR turn up your wireframe and shading quality on the torus, see if this is what you are seeing on the edges