Quality of OBJ mesh

Is the OBJ which is offered in the Matterpak the maximum quality which can be generated from the raw captured data or is this a reduced polygon version to deliver a better compatibility regarding playback on different devices?

How does the Pointcloud Version differ from the OBJ version mesh quality?

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  • Hello Marcus, 

    The OBJ file that is downloaded as a part of the Matterpak is the highest resolution mesh that our system currently produces. The mesh used in Showcase and VR is a derivative of this Matterpak OBJ, however, they are not the same. The Showcase version is highly optimized to use roughly 1/10th of the resources (or less) of the Matterpak OBJ for faster web streaming. That said, when it comes to the overall quality of the Matterport OBJ, there are actually several key factors you should keep in mind:

    - Size and complexity of the Space 
    - Density and location of the scan points and 
    - Interference from things like sunlight, mirrors or similar. 

    Currently, Matterport OBJ’s are optimized to about 500,000 faces (triangles). The exact size varies, but the majority of the time they are right in this ballpark. What you need to keep in mind is that the larger or more complex a Space is, the more these resources need to be stretched to create it. And the further these resources are stretch, the lower the quality of the mesh throughout. For a typical small home, (under 1500 sqft) this is rarely an issue. But once you get above 4000 or 5000 sqft, it becomes much more noticable. 

    The complexity of the Space also affects this greatly. Empty rooms with flat walls require far less resources than round tables. The more “stuff” in a Space, the sooner you will start to see issues regardless of its actual square footage. For the best quality OBJ mesh, it is often better to break up very large Spaces into smaller parts and then use multiple OBJ. A two story home could be broken up by level, or extremely large venue could be broken up sections or rooms. 

    If your goal is to have the best OBJ quality, scan density and location are equally important. Making sure the floor plan in the Capture App is completely filled out (no blank holes). Is a great way to get started on both of these. Adding a few extra points that are higher or lower than you would normally scan will also help fills in gaps under or on top of things. 

    That said, too much of a good thing can also cause problems. While more scans are generally helpful, you will hit diminishing returns very quickly. Depending on the size of the room, going from 3 scans to 6 scans will help a lot. Going from 6 scans to 12 in the same room, however, may just be overkill. Empty rooms require less scans than rooms that are completely full of furniture or other things. 

    Specific to location, try to avoid putting the camera too close to walls or other objects. If the camera is too close, it can sometimes cause artifacts in the mesh data. Ideally you should keep the camera about 1.5 feet away from walls and objects. If you do not have that much room (in a small hallway for example) then do your best to center the camera so that it is as far from the two walls as you can get it. You should also avoid putting the Camera in the center of a door frame as much as possible. Either side of the door frame is generally fine, but right in the middle will tend to cause trouble. 

    Lastly, watch out for natural sunlight, mirrors, glass, and other highly reflective or polished surfaces as these can cause issues when scanning. Direct sunlight will prevent our camera from capturing accurate depth data. This in turn will lead to large holes in the OBJ. Scanning at night, or with the curtains closed could make a huge difference in the end result. Likewise, be sure to label mirrors and other reflective objects inside the Capture App. 

    If you keep all of this in mind when scanning, then you should see a marked improvement in your OBJ mesh files. That said, there are still limits to what our system can pick up, and the quality you can expect from a Matterport OBJ. Small, fine objects, such as wires or railing are often too small to properly capture with our system. While our mesh is generally accurate to 1% or better of the real world Space, things smaller than 2 inches (5 cm) tend to get a little lost in the data and are often optimized out. Likewise, if you are looking for a perfect, “game ready” or movie quality mesh, then Matterport may not be for you. While our Meshes can be (and have been) used in the creation of both, without a bit of manual clean up, they are not necessarily ready "right out of the box" as they would say. 

    With regard to the Point Cloud data vs the Matterpak OBJ, they are both based on the same source data, and while being different formats, their accuracy is fairly comparable from one Space to the next. 

    I hope all of this information is helpful, 

    Best, 

    Keith S.

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