creating an egg shaped solid

I am using ACAD 2000 and trying to create a solid that is something like an egg, kind of. What i actually need is an eliptical sphere, if that makes any sense. My only idea was to try and REVOLVE an ellipse around an axis that would go from the bottom and top quadrants of the longer end of the ellipse. It didn't really work out. So if anyone understands what I'm trying to say and can shed some light on this for me, that would be great!

Thanks!

John

draw an elipse then draw a line down the centre,then trim one side of the

centreline so you only have one half.

then revolve the one half around the centre line. thats how i would do it.

G

Oh, you could use arcs to create a profile.

once you have the desired profile use PEDIT to convert the arcs into a polyline and also to join them as one polyline.

Then revolve it around an axis.

G

You can use the REVOLVE command if the shape is a closed polyline and the shape does not intersect the axis of revolution. So draw a line between two opposite quadrants of the ellipse and slice the ellipe using that line segment as cutting edge. Close the shape by adding the line segnent to the remaining half of the ellipse (usinng PEDIT > JOIN). Now you can use the REVOLVE command.

This is the same thing as G descriebed in the first post, just I added some details and an observation: before you draw the ellipse, set the PELLIPSE system variable to 1.

That was easy enough! The shape came out exactly how i wanted it and I now understand the use of the PELLIPSE function.

Thanks again,

John

Here's an eggy solid, drawn with closed pline and revolved.

Could have used 2 spheres unioned.

Nick

Mr T, is AutoCAD Zone your site? I noticed it had the same address as your egg.

http://www.eezylearn.pwp.blueyonder.co.uk

http://www.eezylearn.pwp.blueyonder.co.uk/images/egg1.jpg

Flores

Mr T, is AutoCAD Zone your site? I noticed it had the same address as your egg.

http://www.eezylearn.pwp.blueyonder.co.uk

http://www.eezylearn.pwp.blueyonder.co.uk/images/egg1.jpg

 

Flores

Aye it is indeed. Not updated much but it's my site. Mainly to showcase my pupils work. They do produce industry standard stuff.

Nick

this is amazing (sample drawings and autolisp):

http://www.takayaiwamoto.com/Egg_Draw/Real_Chicken_Egg.html

I would use a spline to create the profile to define an egg. To ensure that the egg does not come to a point the slope of the spline should be perpendicular to the axis of the egg. This can be achieved by controlling the location of the second and next to the last CV (Control Vertex) of the spline.

In the picture below I drew a vertical line (cyan) to define the axis of the egg (I drew it on top of a picture of an egg). I made a copy of the line directly to the left to provide me with two points I could use to define the spline's 2nd and next-to-last vertices. Turn off ortho mode then define the CVs of the splineusing SPLINE M CV. The 3rd through 3rd-to-the-end CV's can be moved to refine the profile. Next define a region from the spline and axis line and then revolve it. The shape on the right is the AutoCAD solid for the egg.

~Lee