CanHaptics Project Iteration 2: Compiling the tools

Iteration 2: GUI of HaptiColour


We are building a haptic-assisted coloring platform for novice artists and
enthusiasts based on the Haply 2-DoF device. The goal is to create a tool that people can use for coloring 2D shapes with haptic assistance to (1) improve fine motor skills and (2) reduce anxiety and increase mindfulness.

How we got started on Iteration 2?

We faced several coding issues in Iteration 1 and realized our code could have been more effective. We gathered that each of us approached the coding differently and hence decided to have a co-coding session to reflect and learn from each other. Before diving deep into the design phase, we decided to identify our main focus. We crossed-off some items from our pre-planned list — adding non-geometric shapes, generating automatic 2D stencil — as they might have deviated our attention from the main goal of creating an engrossing haptic coloring experience and refining it.

During co-coding, we revisited our discussion on different Haptic Guidance techniques (explored by Marco) and how can we make a curved wall (we decided to do this later in the design stage)

Who did what?

We decided to divide our work again into three parts :

  1. Linnea improved upon the interface to create a UI almost completely controlled through the Haply, she worked the issues that came out of the first round of UI/UX testing.
  2. Marco added haptic guidance element to the walls and haptic feedback to UI elements, generated textures for the texture bank, created a questionnaire to get feedback on textures.

The first round of UI/UX testing

As we are going for a mindfulness application, any small issue in the program can hinder the pleasant experience. So, I did an initial round of testing to see if everything works properly after integration and nit-picked on UI/UX things that can be improved. Shown here are some identified issues:

Where is my brush? No visible tooltip. Also, there is white padding as the brush is not touching the wall.
That offset!!! The brush is at an offset from the cursor (small dot) which leaves unwanted color traces; also the cursor is too small and not noticeable
Field testing! Making a cursor larger and testing the offset. As you can see, the offsets are different for different positions on the canvas.
Why is the color leaking? Colors leaking beyond the boundaries might lead to an unpleasant user experience.
Initial color spill! After starting the program, the brush would leave a splotch of color on the canvas.

Increasing the workspace dimensions

While working with textures I realized if you move the end-effector of Haply doing a short-stroke you might not feel the texture that you feel while doing a longer stroke. I thought increasing the workspace might mean that the user can do a longer stroke on Haply when the cursor on the screen moves a shorter distance. That exploration didn’t work out so well. Might go back and check that out again. If you have any suggestions feel free to comment! 🕵️‍♀️

The workspace and wall spacing increased but the Haply force field didn’t shift. You can see the top corner rectangle guided by the force field and the actual bounding wall which is far out.

Integrating textures

The textures I created used the basic damping wall element. The wall acts as a tactile pixel or taxel. To create variations in textures, I played around with horizontal (gray square) and vertical grids (purple and brown square). I also thought of using a criss-cross pattern but it didn’t provide a unique haptic sensation, it just felt like a normal damping square. Increasing the width of each taxel, created a smoother texture (like a brush), and decreasing the width made it rough (something like a crayon). The textures created by Marco used the variable force field on the cursor (more info here).

This is the GUI for the Texture bank we shared with the class for feedback, first five textures were added by Marco (read more about them here), and the last three textures were added by me.
/*texture specific code*********************************************/
space = 1.2;
wall_h = 1.3;
wall_w = 0.1;
jloop = int(ydim/2);
iloop = int(xdim/space);
opacity = 0;
for (int j = 0; j<jloop; j++) {
for (int i = 0; i<iloop; i++) {
tgrid[j][i] = new FBox(wall_w, wall_h);
tgrid[j][i].setPosition((i+1)*space, (j+0.8)*2);
tgrid[j][i].setFill(40, 62, 102, opacity) ;
tgrid[j][i].setNoStroke() ;
A grid of damping elements that gives a brush-like texture effect
A grid of damping elements that gives a crayon-effect
if(((playerToken.h_avatar.isTouchingBody(colorSwatch[0])) || (playerToken.h_avatar.isTouchingBody(colorSwatch[1])) || (playerToken.h_avatar.isTouchingBody(colorSwatch[2])) || (playerToken.h_avatar.isTouchingBody(colorSwatch[3])) || (playerToken.h_avatar.isTouchingBody(colorSwatch[4])) || (playerToken.h_avatar.isTouchingBody(colorSwatch[5])))) {
playerToken.h_avatar.setDamping(850) ; //850
else {
if (drawingModeEngaged==true){
playerToken.h_avatar.setDamping(680) ;
playerToken.h_avatar.setDamping(0) ;

FBox touchWall ;
for (Wall item : wallList) {
touchWall = wallToWorldList.get(item);
if (C.isTouchingBody(touchWall)) {
playerToken.h_avatar.setDamping(damp); //820
void textureUpdate() {
for (int j=0; j<jloop; j++) {
for (int i=0; i<iloop; i++) {
if (playerToken.h_avatar.isTouchingBody(tgrid[i][j])) {
tvar = 1;}

Hapticolour Iteration 2

After integrating different components, I tweaked the parameters of world gravity (100) and avatar damping (680) again just to make sure everything works coherently. Marco added the damping halo wall guidance effect (more here). I added the vertical taxel grid here as it felt the best according to me and our survey respondent. Linnea added several new buttons and functionalities — buttons to increase and decrease the brush size, save and clear the sketch, an eraser to clean a particular area, and buttons for palette selecting (more here).

Final coloring test! Linnea added two color palettes — rainbow and pastel rainbow. My favorite is pastel rainbow! What’s yours?

Testing for Iteration 3 already!

One of the strange things, I noticed is that the texture granularity is more prominent on the left side of the canvas as compared to the right. It is something I need to dig through. Some of the UI functionalities also need further improvements in the next round.

In the current code, if you keep your cursor on the next palette or prev palette button, the palette will continuously change, which might make it harder to arrive at the right palette. While designing, an interaction of quick touch was assumed.
We need to set upper and lower bounds for the cursor size. Going outside a permissible range throws an error.
The “saved” text disappears very quickly and couldn’t be noticed. Also, several replicas of the same picture are saved if you press the button again and again. The UI assumes that you will save only after you have done some coloring; if you save an empty canvas, the program crashes.

What’s next?

We integrated a promising texture and haptic guidance effect in our interface for now. We might add more texture options based on the feedback on the texture bank. Linnea started exploring the visual effects that will go with the tooltip. I found several resources that could help us add an enriching multi-modal aspect to the current version — brush texture, pixel flow, generative watercolor, brush strokes using bezier curves, paint sounds, processing sound library. For this iteration, we used the same 2D sketch stencil as a base, we might explore more intricate designs that will make the coloring experience more enjoyable and rewarding.