Designing Creative 3D Works: Plan, Design Rules, Animation and AR

Plan a 3D work before you build

A good 3D work begins on paper, not on the computer. Ask three questions.

• Who will use or see it? (a child, a shopper, a student)
• What should it do or show? (teach, sell, tell a story)
• Where will it be seen? (phone, big screen, print, AR)

Then make a quick sketch with a front view and a side view. A sketch is cheap to change. A finished model is not.

Build with simple shapes

Every 3D object can be built from simple shapes called primitives: box, sphere, cylinder, cone. Start with big shapes for the main body, then add small shapes for details. This is called blocking out.

Keep the number of shapes small. A model with fewer faces loads fast on a phone. Keep the names of the parts clear (body, head, arm) so you can animate them later.

Design principles: balance, proportion, contrast and focus

Design principles are simple rules that make a work look right.

• Balance: the left and right sides feel equally heavy. A line down the middle helps you check.
• Proportion: the size of one part compared to another. A toy with a big head looks cute; a head far too big looks wrong.
• Contrast: dark next to light, or one bright colour among calm colours. It makes the important part stand out.
• Focus: the eye should know where to look first.
• Unity: use few colours and one style across the whole work.

Colour has meaning too: red warns, green means go, and blue feels calm. Check that people with weak colour sight can still read your work, so do not depend on colour alone.

Animation: keyframes and in-between frames

An animation is many still pictures shown quickly. Each picture is a frame. Films use about 24 frames each second, and games often use 30 or 60.

We do not draw every frame. We set keyframes: the important poses, such as arm down at frame 0 and arm up at frame 24. The computer works out the frames in between. This is called interpolation or tweening.

• Time at 24 frames per second: 24 frames = 1 second.
• Easing makes motion start slowly and stop gently, like a real object.
• Move only what needs to move, and keep the motion short and clear.

Augmented reality (AR) works

Augmented reality puts a 3D model on top of the real camera picture. Virtual reality (VR) replaces the real world completely. AR only adds to it.

How AR keeps the model in place:

1. The camera looks for an anchor: a printed marker, a flat table, or a wall.
2. The phone finds its own position and angle using the camera picture and motion sensors.
3. It draws the model at the anchor, from the phone's point of view, many times each second.

Tips for AR models: keep them light (small file), use real-life size, add soft light, and test in a room that is not too dark.

Try it: your own small 3D work

Do this at home or in a free 3D tool:

1. Sketch a toy on paper. Write who it is for.
2. Build it from 4 or 5 simple shapes.
3. Check balance with a middle line, and change one proportion.
4. Make two keyframes (frame 0 and frame 24) and let the tool fill the rest.
5. If you have a phone, try an AR viewer and place your model on a table.

In the 3D above, first guess what the arm will do at frame 12, then drag the slider and check.

Key formulas and definitions

• Animation time (s) = number of frames ÷ frames per second
• Number of frames = seconds × frames per second
• In-between value = start + (end − start) × (frame ÷ last frame)
• Key terms: primitive, keyframe, interpolation, anchor, AR, VR

Worked examples

Common mistakes

• Starting to model before planning. You build the wrong thing and must start again.
• Using too many details and colours. The work becomes messy and has no focus.
• Setting a keyframe on every frame. Set only the important poses and let the computer fill the rest.
• Thinking AR and VR are the same. AR adds to the real view; VR replaces it.