- What is Previzion®?
- Does Lightcraft produce and make 3D backgrounds? What about 3D assets?
- Can I rent a Previzion system?
- What software is required to create 3D assets for Previzion? Does Previzion support 3DMax? What about Modo?
- How does Previzion integrate with my existing tracking pipeline?
- What is TakeConverter?
- What cameras can I use with Previzion®?
- What lenses can I use with Previzion?
- Can I use an external keyer like Ultimatte?
- Can we integrate Previzion with my existing encoded cranes?
- Does Previzion record video? What formats can Previzion record in?
- How much delay does Previzion add to the video signal? Is there any delay in the output signal?
- Can I use Previzion in a multiple camera shoot?
- Can the Previzion output be Genlocked?
- How do I use Previzion in Stereo 3D shoots?
- Why use CgFx shaders?
- Can I use CgFx shaders in 3Ds Max?
- What kind of real-time dynamic lighting can I use in Previzion?
- What video formats are supported?
- What hardware or software is required to work with Previzion?
- What additional equipment is recommended for a Previzion operator?
- How many fiducial targets do I need to have? How high can I put the fiducial targets on the ceiling? What about the wall or floor?
- How good is the keying in Previzion?
- What is better for keying: Green or Blue?
- What kind of background/Training should a Previzion operator have?
- How long does it take to get ready to shoot?
- How long does it take to set up the fiducial targets?
- Can Previzion be used outdoors?
- How good is the 3D tracking data?
- How can I get live tracking data from Previzion?
- How do you handle lens distortion for wide angle lenses?
- Can Previzion playback videos as part of a scene? How many video clips can Previzion playback simultaneously?
- How should I shoot my background video plates
- Can Previzion work with film cameras?
- What happens when the intersense camera gets blocked?
- How do I animate a character inside previzion
- How many polygons can I use?
- How many textures can I use?
- Can I use slow motion, or high framerate shots in Previzion?
- How long does it take to train my operators?
What is Previzion®?
Previzion is an award winning real-time VFX and camera tracking software that, in combination with Lightcraft Technology sensors, can take in live camera images, and key, color and composite CG elements in real time. In other words, it’s an entire visual effects pipeline in a single system. Previzion can be implemented in existing VFX pipelines as the hub that brings post-production capabilities to set.
Does Lightcraft produce and make 3D backgrounds? What about 3D assets?
Lightcraft Technology is a hardware manufacturer and software developer. Lightcraft focuses on Previzion engineering and sales, but many of our customers rent their systems and provide production services such as asset generation and on set support.
Can I rent a Previzion system?
Lightcraft Technology is a hardware manufacturer and software developer. We focus on system sales, but many of our customers rent their systems and provide production services such as asset generation and on set support. Contact email@example.com for a list of our customers who rent systems around the world!
What software is required to create 3D assets for Previzion? Does Previzion support 3DMax? What about Modo?
All 3D Packages are supported to varying degrees as long as they can output an FBX file or a Collada file. Maya 2012 is the most compatible, because it’s exporter is able to embed CGFX shaders. Contact firstname.lastname@example.org for more details.
How does Previzion integrate with my existing tracking pipeline?
Depending on the type of application, the tracking data coming from Previzion may be used directly in your 3D compositing software of choice. In other application, you will want to use a post-production tracking software like SynthEyes, Flame or Boujou, but always starting with the Previzion tracking data as a start, which saves valuable time during post. You will need to use TakeConverter to convert Previzion Takes into the desired format.
What is TakeConverter?
Previzion records tracking data in a open source Collada format. This format contains camera position, lens information, rotational information, etc. This is what we call “Previzion Takes”. “Previzion Takes” can then be converted to other file formats using TakeConverter. The Previzion tracking can then be used by your prefered post-production tracking software as final or seed tracking data. TakeConverter is able to convert “Previzion Takes” into: Maya (ASCII), Nuke (.chan), SynthEyes (object/camera), and Flame (ActionScript).
What cameras can I use with Previzion®?
Just about any camera to some degree can work with Previzion, but for the best results we recommend a professional level camera with HDSDI output, and a mechanical lens with hard stops on zoom and focus. Previzion is fully compatible with RED cameras (One/Epic/Scarlet), Arri cameras (D21/Alexa Plus/Alexa Studio/Alexa 4:3), Canon Cameras (C500), Sony cameras (F65/F55/F35/F23/F5/F3) as well as a variety of broadcast ENG cameras (Ikegami, Sony, Panasonic, JVC, etc.).
What lenses can I use with Previzion?
Most all cinema and broadcast lenses can be used with Previzion. Some cinema lenses will need an encoded follow focus (lens controller) unit to output lens data into Previzion. Contact email@example.com with specific lens model to verify that a lens and lens controller is fully compatible.
Can I use an external keyer like Ultimatte?
Yes, but currently you will lose Previzion functions like 3D tracking mattes, and the ability to have CG elements in front of your live action image.
Can we integrate Previzion with my existing encoded cranes?
Yes, we currently support Mosys and General Lift encoded cranes, and we have a generic serial protocol that any manufacture can write a live tracking output for.
Does Previzion record video? What formats can Previzion record in?
Previzion is not a video recorder. We can record tracking data, but not video. It takes in HDSDI video signals and outputs HDSDI.
How much delay does Previzion add to the video signal? Is there any delay in the output signal?
Previzion requires between 4-5 frames from the HDSDI input to the HDSDI output to track, process, and composite an image.
Can I use Previzion in a multiple camera shoot?
Yes. Each camera will require its own Previzion system. This includes our video breakout system, Previzion computer, and some sort of tracking sensor like the Airtrack and Intersense. Multiple systems do have the ability to be in the same coordinate space as well as have a master/slave control of one another over the network.
Can the Previzion output be Genlocked?
Previzion now includes a built in software/hardware frame syncronizer. Existing customers need to update to a Previzion version after 7970 to use this feature. For more info see our documentation page.
How do I use Previzion in Stereo 3D shoots?
Previzion does not do the composite in stereo 3D, but it can record and track the stereo metadata from encoded rigs. We currently support Element Technica and Cameron-Pace stereo rigs.
Why use CgFx shaders?
We use nVidia’s cgFx shaders because they are easily customizable shaders and are very good for real-time applications. These cgFX shaders can only be fully authored in Autodesk Maya.
Can I use CgFx shaders in 3Ds Max?
No. Max’s CgFx implementation is not the same as Maya’s implementation. You may use 3Ds Max to author your geometry, but you will need to run the scene through Maya to apply CgFx shaders.
What kind of real-time dynamic lighting can I use in Previzion?
Previzion does not currently support real-time lighting. All lighting in Previzion scenes are “baked” lights. This allows for high quality real-time rendering.
What video formats are supported?
Currently Previzion supports the following formats:
- 1920 x 1080 px – 59.94i
- 1920 x 1080 px – 29.97 PsF
- 1920x 1080 px – 29.97p
- 1920 x 1080 px – 25PsF
- 1920 x 1080 px – 25p
- 1920 x 1080 px – 23.98 PsF
- 1920 x 1080 px – 23.98p
- 1280 x 720 px – 50Hz (outputs 1920 x 1080 px – 25 PsF)
- 1280 x 720 px – 60Hz in 24fps (outputs 1920 x 1080 px – 23.98 PsF) RED One
What hardware or software is required to work with Previzion?
For using Previzion on the day of the shoot, Previzion is a standalone keyer, compositor, coloring, camera tracking and monitoring software. For creating scenes with complex visuals, Autodesk Maya 2012 is necessary for generating a proper FBX scene with CgFx shaders. For streaming animated characters to Previzion, you will need to use Autodesk MotionBuilder 2012 or Autodesk MotionBuilder 2013.
What additional equipment is recommended for a Previzion operator?
We recommend that a Previzion operator has in his kit: a metric measuring tape, spare HDSDI BNC cables, a portable HDSDI monitor, a video recorder (Pix 240i, KiPro) and pen and paper, laser tape measure. If you show is going to be “finished in camera” or without post it is a very good idea for the Previzion operator to have a large HDSDI color reference monitor with scopes, so they can judge color correction and keying accurately.
How many fiducial targets do I need to have? How high can I put the fiducial targets on the ceiling? What about the wall or floor?
The number of fiducial markers will depend on the distance between the camera and the fiducial markers as well as the size of the stage. For higher ceilings, we make the fiducial markers larger. At any time, at least 4 targets must be visible to the Intersense camera to maintain tracking lock. The maximum recommended distance for ceiling targets is a height of about 25 feet from the floor. We have a calculator available on the downloads page which will give you an idea for the approximate number of boards you will need. The fiducial markers can be placed on the wall, ceiling, floor and even outside. The only placement rule with them is that once they are placed, and surveyed they should not move relative to one another.
How good is the keying in Previzion?
Under the right conditions, the keyer is capable of final quality results. This means the correct background color (generally Composite Components’ Digital Green® for indoor, or Digital Blue for outdoor work or where green is not an option), and very even greenscreen lighting. Several shows are already finaling shots in real time with Previzion and the above combination. Shots with a green floor visible are problematic due to the amount of spill that reflects off the floor directly onto the characters, as well as highlighting small imperfections in the tracking. Practical floors are the way to go if the production can make it work.
What is better for keying: Green or Blue?
For most applications, green is a better choice. However, on some applications, where wardrobe, set pieces or characters require green, blue is necessary. Blue will require twice as much light as green. As long as the green and blue colors being used match the pureness of Composite Composite Company’s Digital Green® or Digital Blue®, with the correct lighting, either color works.
What kind of background/Training should a Previzion operator have?
We recommend that a Previzion operator have either on-set camera background (camera assistant, MoCo operator, etc.) or 3D compositing/animation experience. Previzion touches many different areas of VFX and requires a specific type of person to keep track and troubleshoot adjustments under high-stress situations.
How long does it take to get ready to shoot?
To set up Previzion on the day of the shoot, it takes less than 30 minutes or so. It is necessary, however, to have a full pre-shoot ‘tech day’ to prepare the stage and calibrate lenses that will be used during production.
How long does it take to set up the fiducial targets?
It should take only a few hours to mount and install ceiling targets. For faster non-permanent installations, we recommend using our “Portable Floor Boards” or “Floor targets”. These can be rolled out and quickly deployed when ceiling targets are not an option setup time takes as little as 5 minutes.
Can Previzion be used outdoors?
Yes, absolutely! Our customers have used our optical/inertial trackers, as well as encoded cranes, sliders, and dollies outdoors. We have even implemented differential GPS systems for outdoor use with Previzion.
How good is the 3D tracking data?
The real time tracking data is quite good, but in cases with a very obvious live action/CG interaction, you”ll be able to see a few pixels of slip. In closer shots, without ground contact, the data is basically final quality. In cases with intense ground contact, there are a couple of routes to take. We built a pipeline to take our data into Boujou and Syntheyes (as well as Nuke, AE, etc.) so you can use the Previzion data as a ”seed track” to drive the Boujou or Syntheyes solve. If you’re using 3D Equalizer or Matchmover, it would be very straightforward to add an export for these as well. This usually helps the solve quite a bit, as our focal length measurement is very accurate. Actual productions using this combined pipeline report speed increases of 10x in their 3D matchmoving; shots that took 5-6 hours to track now required only 30 minutes.
How can I get live tracking data from Previzion?
Previzion outputs tracking data over an open TCP/IP protocol, as well as HDSDI embedded tracking using the SMPTE 315M protocol. We also have a plugin for Motionbuilder called “Precam”, which is able to receive live tracking data from Previzion.
How do you handle lens distortion for wide angle lenses?
We measure lens distortion as part of our lens calibration process. We render correctly distorted geometry in Previzion, to show as clean a match as possible. We store the distortion data along with the rest of the lens data on a per-frame basis in our Collada data take files. Getting the distortion into post production, however, is a bit trickier. Each renderer has its own parameters for measuring distortion. Fortunately, we wrote a whole separate tool called Take Converter to extract the data from Previzion takes into a variety of external formats. Adding another exporter is very quick for us, so it”s a matter of targeting which specific pipeline is in use. The basic question is figuring out where to apply distortion in the pipeline. It”s usually done in the compositing stage.
Can Previzion playback videos as part of a scene? How many video clips can Previzion playback simultaneously?
Yes. Previzion can decode HD resolution videos in MPEG2 and 4K resolution videos in H264 (MPEG4) as CG elements in a scene. Depending on your Previzion hardware and project frame rate, Previzion can decode:
- Up to 8 HD Video Plates (at 23.98 fps)
- Up to 3 4K Video Plates (at 23.98 fps)
How should I shoot my background video plates
Use a perspective simlar to what you want your final shot to look like. A big thing to keep in mind when using Previzion to play background videos is that Previzion is creating an illusion using a flat image. This means if the camera goes to far to any side of the video plane the background will start to look 2 dimensional. For that reason it is important to create plates that are from a similar perspective in terms of camera height, and perspective to what you plan to use on shoot days. Click here for more info
Can Previzion work with film cameras?
Previzion requires a HD video signal to work with; this can be generated by the new Arri HD video taps. The Arri taps record the full width of the imaged emulsion, which is critical for Previzion”s through-the-lens calibration system. Most film cameras accept LTC analog linear timecode for audio synchronization; this same timecode can be embedded into the video tap”s HDSDI signal and used to match the motion of the camera move data to the film frames. Standard definition video taps would need to be upconverted to HD before working with Previzion. There are some converters that should do this well (AJA”s FS1). Upconverting a SD signal may cause difficulties when trying to calibrate lenses; a workaround in this case would be to calibrate the lens on a 35mm digital camera, and then move the lens over to the film camera. The lens parameters remain identical when changing from one camera to the next.
What happens when the intersense camera gets blocked?
Should the Intersense camera get blocked, the system is able to hold it’s position for a few moments and quickly recover when the camera is unblocked again. The Intersense IS1200, in combination with Lightcraft Airtrack, is capable of acquiring an absolute position based on the fiducial markers’ positions. The two sensors use rotation and acceleration in combination with the optical recognition, which makes for a very robust combination.
How do I animate a character inside previzion
Previzion does not directly do any animation, however it does listen to animation over the network. We have a plugin compiled for Maya and Motion Builder called Prelink which transmits bone and joint information over the network to Previzion. This network animation protocol is also open so if you want to write a plugin for your own application you are free to do so.
How many polygons can I use?
Previzion can render and load up to 12 Million polygons (measured in triangles) in frame rates up to 30fps and about 6 Million polygons (measured in triangles) at 60i. Polygons in Previzion are broken down to triangles for optimal loading and real-time rendering. Previzion only renders what is in the field-of-view of the camera. So the limit of polygon is up to Previzion’s internal renderer.
How many textures can I use?
Previzion can load and render up to 3 Gigapixel textures. We recommend building scenes optimizing the use of textures.
Can I use slow motion, or high framerate shots in Previzion?
Yes, Previzion can be used in slow motion shots and high frame rates. Previzion uses the HDSDI output (sometimes “Monitor Output”) from the camera and this output will always be set to one of the standard HD video formats. For instance, if a camera is set to shoot in 48fps (HFR), its output will still be set to HD (1920×1080) in 23.98fps. This varies a bit depending on the camera and the camera settings. Previzion will take this input and output the same format. When finishing your shot in your compositing software in post, the tracking data in Previzion can be interpolated to match the original 48fps.
How long does it take to train my operators?
Lightcraft Technology offers on-site training for prospective Previzion operators and new owners of systems. Training for a group of less than 10 people typically lasts for 1 week for first level competency. This is providing that the operators already have a background in either CG or digital video. After this training operators should be able to run the system and all of its basic functions, but they will need practice to get fast at the system and to figure out how to use all of its tools together.