Hi all,
I wonder if anyone has had experience making a frustrum. I made one yesterday, but I am not happy with the results.
A rectangle of 84 inches X 60 inches tapers down to a circle of 12 inches over a height of 36 inches.
I tried several approaches, but ended up making a quarter of it by joining segments instead of a circle; at the top at the corners I put aegments along a small radius as well. The large triangular pieces joined at the bottom in a point, I created datum curves to join the segments, and created boundary surfaces to fill each section and merged them together. The popints at the bottom of the large triangles caused the flat pattern to not unfold completely flat.
I truncated the cone by 1/4 inch so these lines do not join at a point any more, and then adjusted the height of the cone and the dia of the circle to compensate. It unfolds flat but now the circle is no longer a circle.
My first try: thickened quilt to the inside.
First try: the corners are not happy. The datum curves come to a point on the corners.
Second try: I put segments along the corners. That solved the corners.
The large triangle sides come to a point at the "circle".
But now it does not unfold flat.
Third try:I truncated the bottom with an offset datum plane. The triangle sides no longer come to apoint.
The circle is no longer round. I suspect it wouldn't be an issue if the top was a square and not a rectangle. Also, the size needed to be adjusted as the opening is now over sized.
It will now unfold properly.
This shows the assembly to a ring of 12" od. The fit is not perfect.
Has anyone found a simple satisfactory solution for something like this?
Sip
Edited by: sip
I wonder if anyone has had experience making a frustrum. I made one yesterday, but I am not happy with the results.
A rectangle of 84 inches X 60 inches tapers down to a circle of 12 inches over a height of 36 inches.
I tried several approaches, but ended up making a quarter of it by joining segments instead of a circle; at the top at the corners I put aegments along a small radius as well. The large triangular pieces joined at the bottom in a point, I created datum curves to join the segments, and created boundary surfaces to fill each section and merged them together. The popints at the bottom of the large triangles caused the flat pattern to not unfold completely flat.
I truncated the cone by 1/4 inch so these lines do not join at a point any more, and then adjusted the height of the cone and the dia of the circle to compensate. It unfolds flat but now the circle is no longer a circle.
My first try: thickened quilt to the inside.
First try: the corners are not happy. The datum curves come to a point on the corners.
Second try: I put segments along the corners. That solved the corners.
The large triangle sides come to a point at the "circle".
But now it does not unfold flat.
Third try:I truncated the bottom with an offset datum plane. The triangle sides no longer come to apoint.
The circle is no longer round. I suspect it wouldn't be an issue if the top was a square and not a rectangle. Also, the size needed to be adjusted as the opening is now over sized.
It will now unfold properly.
This shows the assembly to a ring of 12" od. The fit is not perfect.
Has anyone found a simple satisfactory solution for something like this?
Sip
Edited by: sip