What is Rotoscopy(Part III):

Note:
Footage for_roto_part_III_and_IV, you can download the original uncompressed footage from "Rapidshare" in two different formats. If you like to use image sequence, you can convert the .mov file to TGA format using any editing/compositing/video converter software. Due to file size, I am not uploading TGA format in rapidshare.

http://rapidshare.com/files/449243843/MP4_for_roto_part_III_and_IV.mp4
http://rapidshare.com/files/449250511/MOV_for_roto_part_III_and_IV.mov



To make a cut-out or matte of any character or object from a scene we use rotoscopy. Rotoscopy is also useful for image enhancement; like Color correction, color change, gradation etc. Once the animated matte is developed for any part of the scene through rotoscopy, now you can use it for different purpose. For example: In this scene if you like to create matte for the character, chair and table to change the BG I am creating 8 polygon shapes. How many polygon shapes you have to create, that totally depends on requirement of compositing section, and it will be designed by the TL or Production Head. You can also use combined technique of keying and rotoscopy together. But the keying process is not useful for Stereoscopy conversation (I shall describe further). In this example I shall only use polygon shape.
Before starting the creation of polygon shape, always play the footage several times to get the movement details of character/objects, due to camera movement any object will change the shape, in particular scene. In this example camera is fixed, so one polygon shape is good enough to cut the Table from scene. No animation is required for this shape also. But due to the activities of character, chair is moving, so I need animated polygon shape for character and chair both. Now, maximum movements are in right hand of the character. But in this example I do not required a separate polygon shape for right hand, because its moving inside of body line in front of camera. So in that case nothing to worry due to the maximum movement of right hand, it will consider inside of same polygon shape which I shall create for body. But remember, it will be complicated when I shall use the same footage for stereoscopy conversation (I shall describe it in my next article).

Create all the roto shapes one by. In this example most of the shapes was created at frame number one. And animated in an interval of 16 frames. Check the image bellow, key interval for roto shape 1 in stage 1.

In next step you have to animate the shape in a key interval of 8 frames. Check the image bellow, key interval for roto shape 1 after stage 2.

In this way I animate all the roto shapes. After stage 5 I found that, I am able to complete the animation of all roto shapes for each and every frame. If you follow the same procedure, within a very short span of time you can animate all the roto shapes for every frame with highest amount of perfection.
Stage 3:

Stage 4:

After stage 4, I found that, if I continue the same process; after stage the polygon shape will animate for each every frame perfectly. Sometime it may happen that, the animation is not required for each and every frame. But few production houses like to use frame by frame animation and this habit is also useful for stereoscopy movie conversation. One more thing, in this example I am using soft edge for the polygon shape (value: 0.0005) but in case of stereoscopy movie conversation you can’t use soft edge, this pipeline needs précised polygon shape. When you are using roto shape for hair, you have to remember that hairstyle is important for a character; production may ask you to roto all the hair lines. If production is not asking for that, then you have to maintain the shape of the hair which is carrying the characterization of the character. In black n white format if you get the character that it is actually, then your rotoscopy is ok.
Rotoscopy is a time killing process and needs lots of passions to complete rotoscopy for any complicated scene. For a vfx composition, rotoscopy is must; so a compositor can’t avoid rotoscopy. But smart compositor use different techniques to create animated mask for a scene. Like combination of color suppress, keying, 2D tracking etc. Production houses are using few software dedicated for rotoscopy like “Silhouette”. If you know the rotoscopy process in “Fusion”, “Shake”, “Nuke” etc you can upgrade yourself in rotoscopy, within a very short span of time for any new software.

What is “Rotoscoping”? (Part II)

For a quality keying process (Blue Screen, Green Screen, etc) rotoscoping is most important thing. In keying rotoscoping process can be use in two separate ways; one is “Effect Mask” another one is “Garbage Matte”. If we use any roto shape as “effects mask” it will help to control the area, where you wants to apply the effects of keying in particular area of footage or where you do not wants to apply the effects. But we use roto shape in keying process as “Garbage Matte” when we wants to remove any un-wanted area from the footage which is not required any more to the next level of production/output. So it is quite clear that rotoscoping is very important to control the keying process. Hope the below mentioned examples (created in Fusion) will help to communicate the importance of rotoscoping in a keying process as “effect mask” and as “Garbage Matte” more clearly, .

Example I:

RapidShare Download link: http://rapidshare.com/files/440510630/G_SD_listening_to_music_MS.avi
Footage Description: Sourav acted in front of green screen, when he was student; now he is working in Red Chillies Vfx. Using this footage you can create a composition of a mobile ad, like; he is listening to music and environment is dancing behind him, he is standing in a bus stand, he is standing beside a busy road etc. Now think about a good composition which is suitable for your showreel/demo reel, its free to use. But you can’t use it for commercial purpose.

Original Footage Print Screen:

In this example footage; nothing is important in the scene except the character and his props so you can easily define the area of “Garbage Matte” something like this:

If you create this “Garbage Matte”, then only you can able to concentrate on the details of hair and props. If you study the footage, the movement of the character is very minimum and as we are using keying conception, in that case you can use rough rotoshape to remove garbage area. The keying process will return you the cut-out/matte to composite the character with any BG.

Problem area in Matte:

In this example, rotoscoping as “Effect mask” is also important. When I am using keying method, I am facing problem to maintain solide matte for those area of sunglass where the specular is coming and bright reflection is also coming. For this area I used rotoscoping technique to remove the effect of keying. In that way I maintain this area opaque.

Final output matte/cut-out:

Example II:

RapidShare Download Link: http://rapidshare.com/files/440514181/Movie_07__02981_.mp4
Original Footage Print Screen:

In this example footage a small girl is dauncing; in that case the character is moving very fast in a wide range of area in front of green screen, according to the requirement of the music ( Gazab.mp3). That’s why I have defined the area outside of green screen only as “Garbage Matte” using multiple roto shapes.

You can use one roto shape also; you can also use roto shape very close to character to get more perfect output. But in that case you have to animate the roto shape more accurately. In my example, I had animated the shape roughly.

Final output:

N.B. : In keying process, to support keying, you can do that but in case of stereoscopic conversation and to create cutout/matte of character/object from BG you need 100% perfection. I shall discuss that section very soon with example in “What is “Rotoscoping”? (Part III)”. Your suggestions and comments are always welcome to improve and rectify my knowledge. If you are a professional please do comments on my post, I shall be grateful to you. Once again "Wish you all a very happy and prosperous new year", enjoy.

What is “Rotoscoping”? ( Part I )

For a VFX/Compositing artist “Rotoscoping” is the technique to cut object or objects out of the scene, frame by frame, by creating a musk/matte using any process. In another way, animated mask to cut object or objects out of the scene is called “Rotoscoping”. In VFX/Compositing one more thing is also known as “Rotoscoping”; painting an object or objects out of the scene, frame by frame.

Now a day, “rotoscoping” is an obvious technique for a VFX artist/production house to achieve the desired result for a scene. Not only that, you can convert your 2d images/movie from 2d to 3d(stereoscopic) movie by a software like View D(Developed by Prime Focus) after creating proper matte/alpha channel by rotoscoping technique. In the present scenario if you want to be a vfx artist, rotoscoping is the 1st step to start your career. If you wants to be a good vfx artist, 1st you have to be a good rotoscoping artist also.

In India most of the production houses have the maximum number of artist in rotoscoping department working for a big number of Hollywood and Bollywood blockbusters. They are working for different types of job like conversation, restoration, cleanup, compositing, enhancement etc.

Most popular softwares for rotoscoping are:
1. Fusion
2. Shake
3. Combustion
4. Aftereffects
5. Nuke
6. Silhouette

Almost all the production houses in India are using Fusion, Shake, Silhouette etc. but they are upgrading their pipeline to Nuke very fast. As per my knowledge within next 2 years it will happen that everybody will use Nuke. Fusion is the most user-friendly node based compositing software, that’s why artist always prefer Fusion.

Software maybe any one of the above, it does not matter, just you need to have a good idea and technical knowledge of rotoscoping. If you have it then you can easily get entry into this industry as rotoscoping artist.

If you want to be a good rotoscoping artist then just follow the following things, you will be successful:
1. If you are practicing then, create a layout on the footage as they (production head) do it for their rotoscoping artist.
2. Play the footage again and again to read the movements of object or objects which you have to cut out of the scene in the footage.
3. Now start placing roto shape according to given layout. In most of the case we use roto shape with soft edge and motion blur according to objects motion. But in 95% case of 2d to 3d(stereoscopic) conversation you have to use hard roto shape. It may be blur as per requirement.
4. Now the breakdown of the footage for roto shape animation, say for example the duration of the footage is 96 frames. In step one animate the shape in a breakdown of 1-32-64-96. In step two animate the shape in 16-48-80 and thereafter 8-24-40-56-72-88 in next step 4-12-20-28-36-44-52-60-68-76-84-92 now 2-6-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94. If you follow the same pattern, in next step your rotoscoping will complete all the frames. If the motion of object is not maximum then only you can skip frame otherwise you have to match the animated roto shape frame by frame with 100% perfection, because production houses are looking for that.