Design With Hand Sketching

Now that we've got some basic 3D modeling skills down, it's time to take a step back and develop the most important skill a designer can have: sketching by hand.

Hand sketching as important as thinking for a designer. It helps us describe ideas to others, but more importantly, it's a way of working out designs before committing to 3D modeling. In an hour of sketching at the beginning of a project, you'll quickly solve problems and make design decisions that you would have struggled with later on.


For design drawing, all you need is Letter sized paper (or A4) and a cheap ballpoint pen, but it never hurts to invest in good tools. Design sketching is easier on Letter sized paper because you can move the sheet while you draw, so that's what I'm using in the demo video.

I keep a sketchbook with me at all times with a felt pen so I can make a quick sketch when inspiration strikes. My favorite sketchbook is the Moleskine Reporter with Grid. The portrait orientation makes it easy to draw on either side of the binding, and the grid makes it easy to keep track of scale and eyeball measurements. My favorite pen is the Pigma Micron 03 by Sakura. The felt tip makes it easy to produce different line weights with the same pen, but unlike cheaper felt pens these tend to stay rigid much longer. They're also non-toxic.


Do yourself a favor and go to The Design Sketchbook for their free 83 page illustrated beginner's guide to design sketching, The Design Starter Kit. It covers the technique in detail and has exercises to help you develop your skills.

This guide will help you develop this skill through practice. Although your sketching skills don't need to be spectacular in order design things, it helps to be a bit more confident with a pen and paper when you're fleshing out your ideas. The more comfortable you are with sketching, the more clearly and quickly you'll be able to produce a design concept.

Observe and Think

Any good design starts with observation. Being a designer means constantly scrutinizing the world around you. In The Design of Everyday Things by Donald Norman (a great place to start if you're interested in product design), he spends an entire chapter talking about door handles! A thing that we take for granted, and never give a second thought, is in dire need of improvement according to this guy, and he's right. As a designer, it's your job to observe the little things in your life and identify the ways in which they can be improved.

In the case of the project I'm using as an example in this class, I observed that every time I ride my bike in the rain, my backpack gets splashed with mud. Of course, I could just buy a fender for my back wheel, but where's the fun in that? I like to make things, and you probably do too, so let's design a bike fender!


Good designers borrow, great designers steal. Just about anything you want to make has already been made in some form- count on it. Your best chance at designing something good is doing as much research as you can. Find the good things and bad things about the products you see that are similar to yours and learn from the mistakes and successes of others. Beginners usually rush on this step (I know I did). Take your time and work out a few different designs before you commit.

There are lots of commercially available seat post mounted fenders out there, but I think they can be improved. Most of them are fussy- lots of extra features that don't serve any purpose and distract from the bike.

I have a bare-bones single-speed bike with a coaster brake that I love. It has no gear cassette and no brake handles or cables. Aesthetics are very important to me, and I think my bike would start to look cluttered if added a big fender to the back wheel- these usually have rods that tie back to the brake mounts, and I don't like the idea of how that would look on my sleek, minimal bike.

The SKS X-BLADE 28+29 ZOLL Fender is close to what I want, but it's too big for my purposes (I'm not going off-road). Besides, I attach my rear light to my seat post, so I need a way to integrate the two. Here are some things that can be learned from looking at the commercial versions of what I want to make:

  1. Attachment Method: Almost all of the bike fenders I found use the same attachment method: a semi-circular clamp piece at the end of the fender with a nylon strap that tightens around the seat post. This is clunky by nature since it requires hardware to tighten and loosen the strap. I don't need to design mine to attach this way because... 3D printing! 3D printing allows us to mass-customize. I can print my own, sleek clamp attachment that fits my seat post perfectly without the need for adjustability.
  2. Materials: As I suspected, injection molded plastic seems to be the material of choice. It's resilient, easy to clean, and cheap to produce. I already know I'm going to use 3D printed PLA, so I'm going to have to make structural and geometrical decisions based on that material later.
  3. Dimensions: By looking at other fenders, I can get a pretty good idea of the dimensions needed for the fender to function properly. The fenders that are mounted closer to the wheel are only about 2 1/2" - 3" wide, whereas the ones that are closer to the saddle are up to 6" wide at the edge of the saddle and taper off to about 5" wide at the end. This makes sense because splashing water will naturally spread out as it gets further from the wheel.

Learning to Sketch

Now that we've done our research and have a pretty good idea of what we want to make, it's time to start drawing! This can be an intimidating skill to start using for many people, I know it was for me.

When we're kids, we draw all the time, but we usually put the pencil down somewhere around 6th grade. Drawing is like any other skill- it takes practice to get good at it.

Drawing is nothing but a seemingly endless stream of failures that eventually lead up to a seemingly endless stream of successes. The curve looks something like the diagram. You're going to suck at this in the beginning, but after lots of practice, you'll notice your drawings coming out the way you want them to more and more often. After enough practice, the techniques you'll learn here will be second nature, and you won't even have to think about them. In the meantime, follow the rules taught in this lesson and you'll get better results earlier.

I can't stress enough how important this skill is to a designer. It will save your life. If you're able to sketch out an idea clearly, even with a minimal level of skill, you're going to save countless hours working in 3D later- not to mention having the ability to quickly explain an idea to someone else! If you develop that habit of sketching all the time as a way to solve problems and explore new possibilities, you'll be well on your way to being a good designer.

Drawing Lines

Design sketching is different than what you probably learned in art class. Manmade objects require a different kind of line work to describe them than natural objects do. With design sketching, we don't use "sketchy" lines. We use deliberate, clear, continuous lines. This is because manufactured objects have smooth surfaces, crisp edges, and contours that almost never have organic texture. Using the right kind of line to describe the object in your head makes a big difference.

People always say "I can't draw a straight line". Like every other skill known to man, no one is born being able to do this. A successful drawing is made by applying a handful of rules and techniques that anyone can learn.

Use Proper Posture:The position your body's in when you draw makes all the difference in the world. Keep your back straight- don't crouch and get too close to the paper. Your arm should be able to move freely- don't rest your wrist on the table unless you're doing finely detailed work (small lines).

My vertical lines from down to up don't come out very straight.

My horizontal lines from left to right aren't great either.

Find your Straight Line Motion:The way your arm moves determines the kind of line you draw. When I draw a vertical line on the paper from bottom-to-top, my lines aren't very straight. It's hard to keep them parallel to each other which means I don't really have control over the direction and consistency of the line. The same problem occurs when I draw them horizontally from left-to-right, but when I draw them at a 45º angle from bottom-to-top, they come out much better.

My 45º lines from left to right are the straightest.

Move the Paper: Because my best straight lines come out when I draw a 45º line, I draw every straight line using this motion. I move the paper to get the line in the right place instead of moving my hand and changing the motion.

Ghost Drawing

Before committing to drawing a line, practice the motion a couple of times. this will give you a preview of where your pen is going to go, and help prevent bad lines.

When making corners, let the ends of lines cross over a bit. “Punching” the corners makes them appear sharper.

Before you draw a line, draw what's called a "ghost line". By quickly simulating the motion of your pen a couple of times before committing to the line, you'll get a preview of where the line's going to go. Almost every time I do this, I have to adjust a little bit. Either my hand or my paper usually needs to be moved at least a little bit before I commit to the line I'm about to draw.

This is a very important habit to adopt because it will help you produce good drawings early on- this will build your confidence! It's easy to get frustrated by a stack of messed up drawings and flip the desk over, but if you take your time and adopt the ghost drawing on day one, this is much less likely to happen.

Pro Tip: Don't look at the tip of the pen while drawing a line, look where you want the pen to go. You'll get straighter lines!

Drawing Circles

Circles are notoriously hard to draw. Use the pivot trick demonstrated in this video to get a perfect circle every time!

Orthographic Views

When developing a design through sketching, it helps to look at the object in separate “orthographic” views. Seeing the projected sides of an object helps us understand proportions, scale, and relationships that are difficult to see in 3D.

To understand something complex, you have to look at it in pieces. This is as true in math and history as it is in music and design. The way to break down a design and study it is to use orthographic projection. Simply put, this means drawing an object straight-on from each of its sides. The top, front, back, left side, right side, and bottom are separate sketches and perspective is not used.

As you get better at sketching, you'll be able to draw complex objects in 3D by hand quickly. Even with this skill, it's important to study any object you're designing in its orthographic views.

To create an orthographic drawing, imagine that the object you want to draw is inside a glass box. If you look straight-on at any side of the box, what you see of the object inside is its orthographic projection. By drawing the object from different points of view in this way, we are able to make decisions and solve problems in a localized way. Trying to design exclusively in 3D (whether by sketching or using 3D software) can often result in objects that aren't well thought-out, as you need to see how each side relates to the other.

Schematic Drawing

Quick measurements can be made by laying down your pen and using your thumb to mark the end of the measurement. This helps keep proportions under control.

In the design world, "schematic drawing" usually refers to a design drawing that doesn't yet represent the finalized design. These drawings have most of the important features that describe the object, but will lack the highest level of technical detail and won't have the most precise geometry.

With these drawings, we are testing ideas using multiple views. Think of this process as a series of tests. Basically, you're just saying to yourself "Let's see how it would look if I did this...", then committing this test to the paper. Try out variations on the different features of an object: make things fatter, skinnier, smoother, sharper, bigger, smaller, etc.

When making these drawings, I find it helps to stick to one scale. When all bike seats are roughly the same size in my sketches, I can make comparisons between the different fender designs I've tried out. This makes it much easier to make decisions based on the designs I've tried out.

Usually after a handful of iterations, you can get a clear idea of where you want to go with your design and move on to the detail studies.

Construction lines serve as a guide for hard lines and serve as guides to ensure that the scale and proportions of multiple drawings are consistent.

Detail Drawing

Detail drawings are drawn at a larger scale than the schematic drawings that show the entire design.

With some decisions made on the direction you want to go based on the smaller scale schematic sketches, it's time to start working on the details. These drawings usually have to be larger scale because when you're designing desktop 3D printed parts, the features and components tend to be very small.

Starting with one of the schematic views I've already done (the top view), I move to another part of the page and do a close-up drawing of one of the parts I know I need to figure out early on: the way the fender attaches to the seat post. I decided before I started drawing the details that I wanted mount it using nuts and machine screws, and since I already drew a top view of the whole piece that I liked. I started with this basic shape.

Detail drawings are where we work out assemblies. Screws and nuts are all small-scale objects that require a larger scale drawing to see.

To create a symmetrical drawing, we use centerlines and “mirror” the geometry along them.

It became obvious right away that the nuts and screws should be hidden in pockets within the form of the attachment feature. The scale of these screws might not be quite right (they look a bit small to me), but the general idea is on paper and that's what matters at this stage.


Your homework for this lesson is (you guessed it) draw stuff! If you're taking this course, you've probably got an idea in mind of something you'd like to 3D print. Why not start with your idea and try working it out on paper?

As you draw, ask yourself "what are the problem areas for this design?", "How else could I solve this problem?"

If you take your time and apply the techniques from this lesson, you'll be able to develop your design through sketching and get a clear picture of what you want to make.

In the next lesson, we'll move on to more advanced 3D modeling.


Share a photo of your finished project with the class!

Nice work! You've completed the class project