ovals

[caramba22242]

Don't see a catagory for this so hope you can help.

Circles are easy but how do you draw a perfect oval on a piece of paper or board

[slimfandango]

can you explain the circle on first please.

In return, I'll dig out the oval one. There is a nifty geometric trick to use.

[dougielogan]

Drink 6 bottles of stella and 6 bicardi's then try draw a circle.

Dougie

[ann_h]

If you tie a pencil to a piece of string on a nail at the centre and draw round, you get a circle.

I think if you stick 2 nails in the board, and have a loop of string round them, and run the pencil round then you get an oval. Actual oval depends on distance between nails and size of loop.

[Oneeyedtic]

It is quite easy to draw an ellipse (oval) of any size but I really need a facility for sketching to show you. However, I'll have a go with words - first decide upon the length and height of your oval and draw a rectangle of these dimensions. Then draw two lines so that the rectangle is divided into four equal quarters. Now look at the top left hand quarter and divide the base into a number of equal parts (say four to make it easy)(A) and the left hand side into the same number of equal parts (four)(B). Now go to the bottom line of the rectangle (not the square) and to the centre of the bottom line. From this centre point draw lines that will look like rays of the setting sun through your four points on A. Now go to the top line of the rectangle and to the centre and draw lines like rays again to your four points on B. The intersection of these two sets of lines are points on the circumference of your ellipse which you join together freehand. Repeat this for the other three quarters of your rectangle. Obviously the more divisions you use when you get the hang of it (say 20) the closer your points on the circumference become involving less freehand. I hope this makes sense, but if it needs further amplification please say and I'll have another go !!!

[kempie]

... and this is because an oval (or ellipse) has 2 foci whilst a circle only has 1 focus.

[caramba22242]

slimfandango..circle on ???

oneeyedtic..you mention the top left then go on to mention the left again..do you mean bottom left this time??

[Oneeyedtic]

Just looking at the small left hand rectangle and nothing else divide the bottom of this into 4 equal parts which will leave you with three dots on the bottom line. Then divide the left side of this small rectangle also into 4 equal parts.The length of the parts on the bottom will be different to the length of those on the side.

Now look at the large rectangle enclosing the four small rectangles, go to the bottom of this and then to the centre point. From this point draw lines upwards through the three dots on the bottom line on your left hand side small rectangle. Continue the lines through the dots and well into the small rectangle. It should look like a depiction of the setting sun.

OK so far, caramba ? Please confirm and then I will continue. 

[caramba22242]

you're too clever for me oneeyedtic.

I start with a rectangle of say one inch wide and two inches high.

I draw a cross in this rectangle and end up with 4 smaller rectangles.Lets call the top left Rectangle A, the top right Rectangle B, the bottom left rectangle C and the bottom right rectangle D 

I draw a cross in the bottom left rectangle C and this gives me 4 mini rectangles within rectangle C and then I get confused.This site doesn't allow email addresses but I'll try this. My name is the first part of my email address. I will print the word at instead of the @ and finish with my service provider, Tesco dot net and hopefully you can post me a drawing of what you mean  

[caramba22242]

forgot to put my name. all one word ...boboliver

[Oneeyedtic]

I'll try an e-mail tomorrow sometime but I've not transmitted a drawing before. I will prepare one, put it through the scanner and see if it will go as an attachment. In the meantime make rectangle A much bigger, say 8" wide x 6" high. Imagine that it is a flag blowing to the left on a flagpole. On the right of the flag the flagpole projects downwards below the bottom of the flag 6" as a single line and call the bottom of it where it would enter the earth Z.. Along the bottom edge of the flag put 3 dots so that the bottom edge is divided into four spaces each of 2" and from left to right call the dots W, X and Y. Now, from Z draw a line through Y across the face of the flag and nearly to the top of the flag. Do the same from Z through X and again from Z through W. This is Stage 1. Is this explanation any better ? If so we can use the flag for Stage 2 tomorrow.

[Oneeyedtic]

For Stage 2 go to the left hand edge of the flag and put three dots so that the edge is divided into four equal parts each 1 1/2" long. From the top down call these S, T and U. Now go to Z and travel all the way up to the top of the flag pole and call this R. Now place your ruler from R to S and you will see that it intersects the Stage 1 line drawn through Z Y. Place a dot at the intersection. Now do the same for R T and it will intersect the Stage 1 line through Z X. Repeat for R U which intersects Z W.

Stage 3. Go to the bottom left hand corner of the flag and freehand a curve starting at the bottom left hand corner and joining up the three intersection dots we made in Stage 2 and finishing at R. This is the first quarter of the curve of your oval.

Stage 4. Repeat all Stages for the right hand small rectangle B

Stage 5. Turn your sheet upside down to do small rectangles C and D. It may make it easier to reverse R and Z on your first attempt so that the instructions above can more simply be applied.

As I said earlier, these are rather large spacings just to make the example easier. If I was doing a first class job I might for instance divide 8" and the 6" into 16 parts each to produce more intersecting dots to help me freehand a more accurate curve.

[caramba22242]

many thanks oneyedtic. I think i get your meaning now.

If you can email a drawing that will be a bonus..if not, I have enough to try myself