interaction lab @ wdka

output at 55.4 seconds

output at 56.0 seconds

output at 57.0 seconds

and a link to the source file

here

Fur Project of Jurjen
Source-code can be found here 

Frame 25

Frame 177

Frame 369

Frame 1225

Assignment:
The assignment due on April 7th is to build an example that outputs three frames of animation to postscript.

The frames should be 0.5 seconds to 5 seconds apart - and between the three of them they should convey an idea of witnessing a special moment.

Be creative in both your ascetics as well as the type of animation you use. Think about color, weight, balance, timing and force.

Files from class include an example of saving to postscript, but feel free to use any animation techniques we have covered so far.
Files: http://lab.impssble.com/files/iLab003/_ilab3-algo-003Distrib.zip

Posting:
Post the three frames in order as both jpgs and the original .ps files, making sure to note the amount of time between each frame.

Add a link to the source code of the project to your post.

(src upload very soon!)

We finished our Signing Machine: Drunk Signing Sessions

Source code:
http://work.jurjenversteeg.nl/wdka/ilab/006-SignatureMachine.zip

New source code (Including Texas music and beersounds!):
http://work.jurjenversteeg.nl/wdka/ilab/006-DrunkSigningSessions.zip

Due March 23rd.

Modify the existing mouse recorder (or stroke recorder posted bellow) to create an app that records your signature and draws it over and over again but with the following criteria:
1) The signature is redrawn in a unique way each time. This applies to the actual line and not just the shape. This could be that the signature evolves or it slowly dies or decays, or it evolves.
2) Play with also having the visual representation be effected by the data in the recorded signature.
3) Create a visual style that is unique to your app - not just white on a black background : )
4) The app should run fullscreen.

Posting:
1) Once it is done you should make a post with the title “Signature Machine - your name”
2) In that post you should have a vimeo video showing the app and a link to the files for your project .

Some related inspiration:

Zachary Lieberman - Gesture Machines:
http://www.theremediproject.com/projects/issue12/systemisgesture/

http://lab.impssble.com/uploads/initials_andreas haider.zip

Using one or more of the examples from class make an app that spells your initials where each straight line is a particle animating back and forth. 

Try to use different animation techniques for the different particles - experiment with easing, sin, gravity and forces.

Create a post on the blog titled My Initials - Your Name including the following:

1 - A Vimeo video embedded into the post: [vimeo 0932823] showing your animation. You can use iShowU (mac) or Camstudio (pc) for doing screen recording.

2 - A link to the zipped project code for your assignment.

Here’s the video:

The link for the source code ZIP file:
http://lab.impssble.com/uploads/001-Jurjen-Initials.zip

I’m was working on the audio for our project, and I’m utterly confused now… Spent all night trying to figure this mystery out.

Here we go: within the circle, audio will play.

Easy, calculate the distance to the center of the screen and check if it’s smaller then the radius of the circle.

Now comes the weirdness. Logically it would be something like if( distanceToCenter < radius).

OF does not agree with me on that one…

I have to do this: if( distanceToCenter > radius) to make it work. I’m printing out all the data, and I have no idea what the hell is going on here. Is this some plot to alter the worlds mathematical notations? 0.o

The code.

printscreen with some of the data in the top left, the mouse was in the circle, and the sound was playing.

Mouse outside of the circle, and the sound not playing…

I guess I’m just being stupid, but it just confuses the  hell out of me.

Yes, progress! Since last time there’s been quite some progress. Shapes now move around freely, though not so organic like yet. They rotate as they move, as to move head-forward all the time. Hands in a butterfly shape are automatically recognized and stored. As you can see in the video, the single hand is ignored. I will have to do more testing to see if this recognition really works as well as I hope it does. I need to be sure they do not flutter off the screen, and there’s a small bug in the angle.

PARABOLIC TRACKING SPEAKERS

After looking for examples of parabolic speakers, we decided to use plexiglass as a material. We looked at commercial parabolic speakers at the Ikea,

The back of the speaker isn’t supposed to resonate, we can achieve this by padding the back of the speaker with heavy wood.

we also found a bit of research done by students from the
Royal University-College of Fine Arts in Stockholm, they found just about the right curves for the parabolic dishes.

Here you can see some try-outs, using very simple stuff:
a Dish and a steel tube.

We did some work with firmata and servo’s but have decided to switch to stepper motors and a serial connection wich works a bit more stable.
Here you can see a stepper motor working:

HARMONOGRAPH

We started by getting a collection piano samples - these are pretty high quality.
Now we are making a sound manager class, that only handles these sounds.

Next up: looking into building an ir-camera; we’ll probably by a new one for this.

Here you can see some try-outs (again):
This time with alphablending.

We’ve been working on the Particle class
in which we’ve succeeded to implement into our project.

Now the issue we get confronted with is, combining the different classes.
As there are the Particle-class and our Sms-class.

The Sms-class is our class were we receive incomming messages,
and push them into a VectorArray
But now we get stuck working with these classes,
it feels like a fundumental class-structure missing knowledge.
Both separate classes work fine, though together we get only half of the data.

With some help tomorrow we’re hoping to make a big jump!

Ok what has happened in the holiday….

Not much in the OFwork part of the project. Just before x-mas i made a new video labyrint, according to the last picture i uploadet. It almost works… it just crashes the program sometimes…

Then i have made and LED turn on and of… juhuuu, that works, and the buttons also almost works, i just needs to find the right ones and i havn’t been abel to do that i DK.

I almost have all the OF parts now, i need to make something work on time and then i just need to put it all together!

In the not OF part of my puppetshow a lot of stuff has happened. And i will just post some pictures:

The first is a scetch of how the theater is going to look:

The second picture is the puppets almost done.

Hi everyone,

here are a few stills from what i’ve got untill now. at the moment i’m trying to get the bodies to stick to the heads. i’ve thought of some ways to do it and where to write it in my app but it’s not working at the moment so i’ll have to look at it a few more times;)

Hi, I’m sort of better again… and here’s a little thingy I worked on today. It’s a test of some water like structures I did, to find out the best way to get a watery surface. The framerate of the video is a it messy, but good enough to get the point across. I’ll clean the code a bit, and put in some comments, and post that too.

On another note, I’m pretty much stuck with the particle fish thing. As yesterday was the first day at could look at code again without my head starting to twist at the sight of small letters, I haven’t put much effort in it, but at the moment I don’t see exactly where to go from here, so I’m looking forward to tomorrows particle class…

So, I’ve been in bed all week, flu got me pretty bad. Sadly it also means that there hasn’t been a lot of progress. I’ve been working on a particle tracking a point, combined with a simplex noise number, which is currently working. Also, I’ve been trying to give it a solid sort of “tail”. Which worked to some extent, but not the way I want it to work…
Anyway, here’s a little video.

The framerate is a bit whack, but it’ll get the point across. Goal of this whole thing is to get the shark to make more realistic looking movements towards the target, and not rush in there in a straight old line.

I’m off for tea and bed, goodnight all

edit: can’t seem to get the vimeo thing to work…

Alex

As we talked about before via email…

Technologically the idea is a mixture between this http://www.youtube.com/watch?v=Jd3-eiid-Uw and the infrared head-tracking you started last time. At first it seems only as if i would use a different technology to make the screen bigger (which from my personal wow factor is nice already). But as he said, his technology and concept are not able to track two people….

but this is exactly where it gets interesting, not only would i be capable of tracking two or more people, i want to make the conflict between the different POVs the theme of the work…

so the idea is to start out with a single person, probably only one (or few) three-dimensional basic shape(s), black background… when a another person enters, the object from the perspective of one person morphs into the perspective of the other person, but since both are still there a new object (the synthesis of both perspectives) is created, the morph is less of a new object but much more a visual oscillation between the two (inspired by the gantz graf video but less shiny, less shading, less NURBSy, but i can also imagine a more awkward jodi game-mod variant of polygon dumps, i am less on the slick side)… i have not too much details here, because first i want to figure out of course if that works at all, and mental images always get altered by reality. The sound is going to be based on a granular synthesis were different grains (whose size and distance is defined by the positions of the people being tracked) fight for volume.

A change to the project I’ve made is adding an extra camera to the space,
for motion-detection on the entire bed.

The procedure will now be:

Step 1. Set the alarm. And go to sleep.
Step 2. At the set time, the alarm will go off.
Step 3. Look into the Webcam #1 above you, to silence the alarm.
Step 4. The alarm will go off every 7/10minutes.
Step 5. Once you go out of bed, to turn of the alarm, a question/puzzle/task will be there to be completed.
Step 6. If you complete the task, Webcam #2 will check if you don’t crawl into bed again.
Step 7. If so, go back to “Step 3″.
Step 8. Webcam #2 will be active an hour after you completed the task at “Step 5″.
Step 9. Get yourself a Cup of Coffee/Tea!

Since we’re also doing another project that’s related to parabolic speakers, we figured let’s do this one together - and simultaneously work on the Harmonograph-project too, see pictures below for the book I showed in class.

In the first project we’ll make parabolic speakers (probably 2) that ‘follow’ the people walking around in the installation. So, beams of audio will be directed to the person, and he/she will hear it while other people (not standing in the beam) hear much less - if anything. 

In the Touch Harmonographs project, we’ll try to make an ‘environment’ where people can create harmonographs on the walls (floor?) by drawing a line with their fingers/hand. A corresponding sound will be created.

Week 1. Try to make some harmonograph graphics (hooked to mouse dragged). Upload a screen-capture.

Week 2. Make some sounds correspond with the graphics. (Octave, Chords, see harmonograph booklet). Finish watching Theo’s VideoManager Class Tutorial & start writing classes ourselves.

Week 3. Begin making tools for a touchscreen (Ir camera, Ir lights, surface?). Decide whether to let the walls be as they are - or to put something there to deform the projections. Reserve a beamer (Rental)!

Christmas break?

Week 4. Finishing up the code - testing & trying to make it crash, etc. etc.

Week 5. Making the complete test setup. Fix last problems that occur.

Week 6. Complete project.

And a video: Harmonograph tryouts in O_F - screencapture

———————————————————————–

Tracking Parabolic Speakers:

week 1 - Looking up examples of parabolic speakers - tutorials maybe? First dish tests (speaker + dish & one speaker in tube - picture + video coming soon!)

week 2 - See how to make the arduino + 2 servo’s work with O_F. How to make 2 arduino’s work at the same time? Look for steppermotor-chips. Post more stuff on the blog - pictures/video/progress.

week 3 - Start writing code for face/blob/? -detection - how to track people the most efficient way, etc. 

Christmas break?

week 4 - Make first test-setting - complete writing the code & assembling servo’s + arduino(’s). Final decision which audio to use.

week 5 - Finishing up - testing.

week 6 - Complete project

1. week: Finish the video labyrinth = Creat the structure for the videos.

2. week: Create the arduino connection

3. week: Create the arduino connection + video labyrinth (= prototype)

CHRISTMAS

4. week: Make the setup (test)

5.week: Make the setup (test with real videos and puppets)

6. week: Make the FINAL setup (Final)

The idea, as previously mentioned, is the Katamari Kitchen. (Person as a magnet through a kitchen).
The planning of Lodewijk and me goes as following:

Week 1 Make a test (see how movements and shaking is defined)
(Use particle code ofAmsterdam: placing objects in space. )
Homework - Write attraction target for objects code
Week 2 Look for a bounding box around a person and send particle targets to that.
Also work on Pixelcounting framedifference to detect the shaking.  (make tests to see if shaking has detected)
Homework - Inside the particle code: see if a person is shaking and write the function for shaking.
Week 3 Look for randomness and position (where will the objects stick to the person) make difference between left and right clipping.
Homework -  Work on animation that’ll include gravity. / fine tune
Week 4 Look at detecting blobs over time; in case 2 persons are detected and walking across each other.
Homework - Work on animation that’ll include gravity. / fine tune / extra
Week 5 Work on graphics, sounds and atmosphere.
Homework - Fine tune  graphics/ sounds/  test
Week 6 Combining all objects and test the prototype.

Oh; we indeed haven’t assigned the tasks to into individuals yet. This will happen as we go, as we want to make sure we wont be waiting on each other in the procces

Also an update on the sketch: where the camera is now placed at the beamer position above the person (45 degrees angle).

My concept of the SMS Projection (okay, still need a project title) is that people can send their sms to the screen and play with it, together with other messages from previous users. You can twist, rotate etc the messages by hand.

This is a visual explanation of the concept:

I am still not having a really clear idea about my concept, but I really want to make something that will be activated/manipulated by SMS messages. Almost everybody has a mobile phone, so is able to participate in the project.

As said before: I really like the SwimmingMessageSystem (see favorite projects Jurjen)

Now, on the internet I found this app:
http://smsrecv.narod.ru/

It is an application for PC to receive SMS text messages. I would like to rip the data and displaying/edit the text via OF.

Concrete concept + sketches are coming up soon…

My idea is to make an interactive WakeUp-”system”.
The way it is supposed to work in the end, is something like this:

The night before, you enter a time on which you want to wake up, let’s say 08:00am.

At that giving time, the next morning, alarm-bells, sirens and other sounds will be filling the room.
Above the bed hangs a webcam.
Once the alarms are going off, you have to look straight into the webcam,
which will detect your face.
The webcam will check if your eyes are open, and stay open for at least 5/10 seconds. Then the alarms sound will die out.

This procedure will repeat itself every 7/10 minutes, until you walk out of bed, to switch the system off.

Maybe trying to switch of the system will require you to solve a puzzle or answer a difficult question, just to test, if you’re really awake.

Technical part.

There are some things I really need to take a look at.
Especially the “Eye-recognition”.
I’ll be using the HaarFinder to recognize the face, but then I’m not really sure
how I’m going to check if the eyes are open or closed.

The build of the project can be split into three parts:

One: “Eye-recognition” - Check if the eyes are open or closed.
Two: “Set the Alarm” - Need an inputField where you can specify the time the alarm goes off.
Three: “Switch off the Alarm” - There should be a question or a puzzle to solve to make you shut down the system.

I got 6 weeks to finish the project.

My basic schedule will be:

Week.1: Present my idea.
Week.2: Start detecting those eyes.
Week.3: Proceed Eye-detection + inputField for “AlarmTime”.
Week.4: Finish Eye-detection + AlarmTime + Question/Puzzle.
Week.5: Last tweeks + Test run of the WakeUp-System.
Week.6: DefRun of WakeUp-System

As a little extra, Theo sent me a video of an awesome Alarm Clock, called:

Rise and Shine:

I have made the above sketch to visualize the real life katamari kitchen idea:
1st image: Pans, oven, knifes, spoons stick to you since you passed by.
2nd image: Shaking will cause all objects to fall, making this huge sound.

It may only work when you are standing in front of the screen. It would look really ugly if the camera would detect you from 20 meters away. But how to detect a max distance from the screen? I thought of this:

One cam to capture the person and one camera to detect the distance from the screen by looking at a min x position for the center of max. But I could be terribly wrong. Any thoughts?

- projection vs. physical
- (interactive) table surface
- human body
- sounds
- music
- hands
- SMS messages
- special room?

Above are some keywords which we want to work with.
We don’t have a concrete concept yet, though we want some projections working together with physical elements.

I have an idea of creating this kind of racistic force in OpenFramework, that does something with an video input image. I am thinking the racistic force kind of prefure 1 rather than 0, or in color prefure numbers that can be devided with 2(working with the historygram)…

I have no pictures of the idea, but i imagine some kind of grafhical project related to my 1. favourite project.

By placing your hands in the shape of a butterfly against a certain piece of the wall, and whisper into it, you create, a butterfly! The butterfly has colors related to what you said, the pitch, speed, and volume. They will fly away and live for a few days long. When someone touches your butterfly, it’s message is heard. The butterflies freely fly over and out of the room, even flying over the building and right into the sky. They are alive!

Technically, by placing your hands against ground glass it’s captured from behind, and it’s being rememberd as it records sound. This is then being projected by multiple projectors.

The second idea is a video wall on which every movement is captured, as in a very long shutter speed. Traces left behind by people all have their own colors, and add up to each other. The colors of multiple traces add up and form new colors, etcetera.

1. SwimmingMessageSystem of Nanika (http://nanikawa.com/?p=33)

– What about it interests you?

I find this project very interesting because of it’s ‘making static text-messages’ more dynamic/flexible.
Also the depth of the screens. One very long wall, one line full covered by hi res screens, which means that the “swimming text message” has all the space to swim in.

– What technology does it use? List both hardware and software.

• 24 (HD?) screens
• SMS receiver
• C++ script?

– How does it work?

Youcan send an SMS message to the screen. The system will break up your message into separated words and makes a shape of a fish, swimming trough the water.

– How could it be improved?

Perhaps more visualizing the text-message.
Analyzing what it says and visualizing it.

The first idea I had was some kind of a godzilla thing.

A person’s shadow would be given a tail, spikes and whatever, and rampage around in a city for a bit. The more I thought of this idea, the more I started disliking it, so I haven’t put much time in making a fancy sketch, just horrible sketches on paper (will be scanned later, scanner down).
http://www.worthersoriginal.com/viki/#page=shadowmonsters

After just thinking in class, maybe a more GTA 2 style stuff could be pretty awesome. Quick drawing:

After more thinking I decided to go with a technically easier project, and take time to make it look good. Most of my projects end up technically okay, but looking a bit meh, so I’d like to spend at least two or three weeks on the visual stuff this time, instead of spending all the time on getting stuff working.

The concept:
I want to bring people together by using the relation between their centers of mass to manipulate sounds. The further away blobs (persons) are from each other, the more annoying the sound will be. I also want to make some visual stuff connection the people, connecting them with green visuals when they’re close enough, turning red when they move too far apart. The sounds are easily created by using single notes and altering the speed for different tones.

Here’s a little (bad) sketch I did:

Cheers,

Alex

The idea is to create a portable device that can create postcards or other kind of turist related things.. like an alternative to the drawing protraits you can bye everywhere at turist attractions.

I havn’t fully developed the idea, but this is the first draft…

This is an installation called: Playing the building. It is made by David Byrne, a member of Talking heads, great band.

http://www.youtube.com/watch?v=Gea9SYUdJeY

I just reasently came to know about this project and i just love it.

The idea of the project is that you sit and play on a píano and instead of the piano playing regually piano music, every key triggers a sound around in the building.

In the movie Byrnes kinds of descrips how the installation works, with different machines that are placed around the building and gets switched on and of by playng the piano.

I really love the asthetic and the idea, it has a kind of old building, ghost kind of story to it. It would be cool if it was portable in some kind of way and you could go and make pirate koncerts in deffenrent buildings such as this buildings:

http://farmerwife.blogspot.com/

The above diagram is my vision of how to realize the following concept:
What I like to do is having many objects flying on the screen (such as little balls). When a person is passing by and will be detected by the camera, OpenCV will smoothly move the objects to your founded body contours and stick to it ‘katamari’ style. However, when you look to the screen directly, the camera will detect your face and release the objects of your body immediately (whooosh!). The effect will be as if the little objects are alive: When you are not looking, they follow you and stick to you, but when you look at ‘them’ they will fly off.

Please see the full idea here

While I was in Rome I visited the forum and Colosseum and thought: why should we always imagine stuff that we can really not imagine at all. I want to have a set of glasses to show all those lions eating people, but more importantly, how would it feel walking trough all the markets and see the way people dressed. But since there is such a big difference in what people want, visualization or imagination. i would like to research both, and put them in an installation.

To make things more realistic and closer to everyday-life I imagine the screen to be an actual window and let people see the everyday world in stead of synthesized environments. In this world ill be telling a story that has coherence with the shown images but lets your fantasy do all the animation of the supernatural. Unless of course you want to interact and see things on the screen, thats okey tooooooo. So lets make this a touch screen and if someone presses a certain area of effect (which is found by listening to the story) the foretold animation will be shown for like 5 second before it fades away. Now to make the window believable we need a context for it to exist. I personally would like to create a wall that gives the impression that you are in one of the locations in the story. (Like if the stroy was about a crippled child that imagines all kinda stuff when looking outside of his house, that happens to have a view of the elementary school playground. And he has many things he thinks about when looking at that, he even has stages that conform to a psycological train of thinking, diappointment, anger, relativation, acceptance. If this is all too much we will scale this down) Note that this window will be interacting with the person in a realistic way, this can be done because of the headtracking invented by Johnny Lee http://nl.youtube.com/watch?v=Jd3-eiid-Uw&eurl=http://www.cs.cmu.edu/~johnny/projects/wii/. Of course we have to decorate around the window in order to make it even more realistic and coherant. Oh and only one person can watch this in order to make the headtracking work so a wheelchair would suggests this, even though its still not definitive. All this could result in very immersive experiance I think.

PROJECT 2 While riding the train i listened to music and gathered the notion that spacing out a train-ride with amazing visuals and music would make the ride a lot of fun. Visuals and music have a big coherence. It will have a lot of impact on you. And the train is iconic for traveling from one place to another so that helps when you want to make an installation that shows multiple locations, or movement at all. The thing is that if u switch music, the effect will stay the same, it doesnt matter what music u play, only the beat per minute counts. This will be determined by markers (songs will be provided by us) and the visuals will sometimes be comming at u at the exact rate of those markers. So switching music doesnt change the installation, just the admophere.

So to be exact the 2 projects are:

A window that shows things pass by like a regular window would, only this one is touchscreen and has many hidden animations in it. The spoken story is an itergral part of this installation.

A train window which is a beamer on a screen coverd by a large glass window with video images and music to create a futuristic travel across the earth, space or even the microcosmos.

edit

i just talked to mathijs about my post and he had some very nice feedback: he thought about a device that measures the speed of recurring things outside the train and chooses a similar beat in a track with it… kinda cool huh!

thanks to mathijs aka joke for this idea

Looks like this Wordpress theme can’t handle images that are 600 pixels wide - so for your diagrams please make the images 500 pixels wide max. You can link to a larger image if you need to. But for the blog make sure any image is max 500 pixels wide.

I changed the settings so now the medium image wordpress generates for you when you upload a file will be 500 pixels wide. So you can select Medium as the type to embed and it should look good.

To test -

For next week come up with two projects that you want to make.
The projects should relate to computer vision in someway but can incorporate other techniques as well.

Please keep in mind that this is an 8 week class - so try to have big concepts that are not too hard for you to make. A good example of a nice project that is not too hard is Kyle McDonald’s - I eat beats.

1 - Title of post should be - Your Name - Project Ideas
2 - Post the projects on the blog with a short description text for each one.
3 - Post a clear diagram(s) that illustrates how the project would work.

Csurge
Moving elements on the screen towards your hand position and even of the screen - http://www.csugrue.com/delicateBoundaries/?section=video

What about interests me?
The unexpected awesomeness of elements actually getting out of your screen because of what you do.

technology

• OpenCV
• Beamer
• Monitor

A (multi) touch display made with OpenCV, camera, a beamer and a computer monitor. (I think?) The camera detects your (hand) position on the display and openCV moves objects to it. In case hand is kept longer onto the display, the particles will move towards the biggest blob by beamer this time, starting from your hand position.

When they hand is leaving the divined position, the creature animation will be set again to the boundaries of the fake display.

Improve
The objects move nicely but I think it’s a bit unexciting in matters of colors.

It would be nice to add an actual function to it. It’s fun now, but you can only use it once: for example layer information like so; A text layer with decoration can be visible if you move objects away or even get them off the screen! (or something).

Thema
Creating shapes by making contours with hands. The shapes include gravity. http://www.tmema.org/mis/video/mis_2_negdrop.mpg4

What about interests me?
A very close connection between a person and the app. It totally feels like you are doing this.

technology

• Camera
• OpenCV / OF
• Beamer

I imagine this is done by a form of background subtraction. the app is looking at ‘white’ pixels which are surrounded by back pixels. If this is the case, then this will be a new object with certain attributes (color, animation). So it scans the image vertically and horizontally for black pixels to start and to end in a x or y pixel row…pretty impressive.

Improve
Dont make the shapes disappear, leave them at the bottom of the screen untill you somehow choose to get rid of them. With these particles you can make a nice object on you multitouch display! (even though it’s sort of a different idea)

Front
Using Motion tracking and convert live motion into 3D shapes. They actually sell their design as products. http://www.frontdesign.se/sketchfurniture/

What about interests me?
The function to draw 3D in a easy way while directly seeing the scale.

technology

• 2 infraRed Camera
• Sufficient space
• A monitor to see what you do
• OpenCV

Since this is using 3D, meaning width, depth and height, it needs to capture 3D. It could be done by one camera at front capturing the width + height and one on from the side, capturing the depth. The drawing is done by the hand. The hand is the most far from the center of mass. So you could say if the distance between the first x of the bounding box is higher than amount of pixels start draw. (or lower than)…This seems very complicated.

Does anyone have any thoughts about how this could work?

Improve
You probably can not control the thickness of the lines, they may be very important when designing to the details. Some additional options suchs as those could be useful to apply as you are drawing to have a more complete real life toolkit.
—-
My notes on the wiki.