How to draw cylinders https://www.artistsnetwork.com/drawing-basics-learn-to-draw/ This site Explains how you can use cylinders to draw people.
Understanding cylinders In order to be able to draw a cylinder it is helpful to think of a cylinder as being a circle on the top, and to see the side as essentially a rectangle wrapped around the edge of the circle. If the cylinder is tipped, the top never actually changes from being a circle, however it appears to be an oval. https://design.tutsplus.com/tutorials/how-to-learn-to-draw-stage-3-visual-database--cms-24325
Getting started So, you need to draw the top as an oval. The more it is tipped away from you, the narrower the oval will appear. The bottom of an oval looks like a smile, the top curves like a frown. The bottom of the cylinder has a curve that matches the top of the cylinder. https://math.tutorvista.com/geometry/3d-shapes.html
Drawing a circle and oval To be able to draw a cylinder you need to know how to draw circles and ovals. They are very similar. A circle fits inside a square. An oval sits inside a rectangle.
Start with a circle To draw a circle you first need to draw a square. A circle fits inside a square exactly, touching the mid-point of each of the sides. One way to remember this is to think of a chocolate donut, sitting in a square box. It will leave a touch of chocolate right in the middle of each of the sides. The circle also touches about 2/3 to ¾ up the diagonals. http://jefkalil.com/category/seo/
Drawing a circle Draw all your guidelines very lightly (butterfly weight) Draw a square Draw in the diagonals (corner to corner) This will give you the center of the square. If you draw a line vertically through the center of the square and a line horizontally through the center of the square, you will get the mid-point of each of the sides. (This has been described as drawing a snowflake in the square.) The circle will touch these midpoints of the sides, but it will not flatten out as it nears them. Now you need to find the 2/3 – ¾ mark on the diagonals.
Finding the points on the diagonals To find the 2/3 to ¾ mark you could eye-ball it, however many people find this difficult. So, draw in a diamond. The lines will go from the mid-points of each of the sides. The sides of the diamond will intersect the diagonals halfway between the centre and the corners of the original square, so the ¾ mark will be halfway from the intersection points to the corner. The circle needs to pass through a point just slightly closer to the centre than these ¾ marks. There is a mathematical method to find this point exactly; but it is fine just to come close for most drawings. Connect these points with a smooth curve.
Drawing in the circle One of the keys to getting a smooth curve is to turn your paper as you draw. Most people draw much nicer curves above their hand but as soon as they try to draw under their hand it gets cramped up and tight. Turn your paper to make each section nice and smooth. Look where you want your pencil to go, rather than at the tip of the pencil. It’s like riding a bike or driving a car. Look where you want to go. Bike from: http://www.robintatlowlord.com/
Follow the same steps for an oval You need to follow the same steps for an oval, however you start with a rectangle instead of a square. It is even more important to draw in the diamond as it’s much harder to judge where that 2/3 or ¾ mark is without the diamond. It’s even harder than with a circle to make sure that the oval just touches the mid- point without resting on the rectangle. You don’t want “flat tire” ovals or ovals with sharp points at the ends.
Now to draw a can of soup: We need to draw a cylinder that looks 3-D. In this photo the bottom curve is deeper than the top curve. The top curve is closer to your eye height so it looks flatter, and the oval is skinnier. https://www.campbells.com/campbell-soup/condensed/
Now we need to use this to draw the top of the cylinder Start with a rectangle to create the oval at the top of the cylinder. Draw in the diagonals, and find the midpoints of each of the sides. Mark in the 2/3 to ¾ marks on the diagonals. Draw in the oval
Keep the cylinder symmetrical The curves need to be symmetrical
Drop down the sides The sides need to be dropped vertically from the sides of your rectangle. Cylinders need to have the sides that are equal in length.
The bottom curve matches the top curve The bottom curve needs to match the top curve. Or, you can draw it a little more curved as you go down the cylinder. Make sure the curves are symmetrical, with the lowest part in the center.
Now add a label The label is applied to the can so that it looks straight. The top of the label is the same distance from the top all the way around, so you need to draw it so that the sides of the label are the same height.
The label is the same distance from the bottom, too The bottom of the label should be the same distance from the bottom of the can all the way around
The curve of the letters follows the same curve as the top Letters generally line up at the top and the bottom, and so do the middle lines of the letters.
The letters go straight up and down When you add the letters they need to be written so they are straight up and down, and the tops and bottoms follow the curves. They are drawn wider in the center and more squished on the sides http://www.drawinghowtodraw.com/stepbystepdrawinglessons/ 2014/01/drawing-circles-in-perspective-how-to-draw-circles-and- ellipses-in-correct-perspective/
Now apply this to drawing a water bottle Usually it’s a good idea to do a quick sketch of the object you want to draw. You can make it detailed or just a simple sketch like the one on the right.
Now get the proportions The next step is to draw in a center line and then establish the lines to get the correct width and height. You can use your hand or a pencil as a “ruler” to measure how tall something is compared to its width. Draw your guidelines in lightly Often a soft blue coloured pencil helps you get guidelines that are easily seen under your pencil drawing.
Add vertical guidelines You need to have a centerline and then draw vertical lines equally placed on each side of the center line so that your bottle is straight and symmetrical
Getting the curves lined up Make sure you mark in all the “bumps”. They all start at the same height from the top or the bottom of the water bottle, so they need to be at the same height in your drawing.
Now the curves Each bump and change in plane creates a curve on your drawing. The lowest part of the curve needs to be in the center. Both sides of the curve are symmetrical (unless the bottle has been crushed) The bottom is curved too.
Bottles Work done by other artists https://mineugene.deviantart.com/art/Evian-TM-Water-Bottle-377323839 http://blodgetstudios.com/blodgetart/graphitecharcoal/bottle.htm
Shadows The shadows add depth. These examples are from the web site: http://www.artinstructionblog.com/wp-content/uploads/2009/08/values- sheridoty-2009_img_11.jpg
Once you have the curves look at the shading The bottle you have drawn using lines can now be used as a template under the good paper. This will allow you to use shading to create the form rather than line, which helps to make it look more realistic. Real-life objects don’t have outlines. You can watch this “You Tube” video of a drawing of a coke bottle by Marcello Barenghi. This drawing took 5 hours 42 minutes, and you can watch the speed drawing of this process. He is amazing! https://www.youtube.com/watch?v=RlEhd3 CaHmc