Create a Point Cloud for Use as a Factory Asset24 Aug, 2014 By: Rusty Belcher
IMAGINiT Tricks Tutorial: Don’t waste time modeling your next factory asset — grab a camera instead.
Editor's note: Scroll to the end of this article to watch the video version of this tip. This tutorial courtesy of IMAGINiT Technologies.
Reality capture and point cloud technologies are becoming much more prevalent in today’s manufacturing environment. Today, point clouds and scanned meshes are regularly used design tools for modeling applications and 3D printers. In many cases, you can produce a fairly good quality point cloud with pictures from a handheld digital camera or camera-equipped mobile device, such as a smartphone or tablet.
You may wonder why you’d want to use a point cloud instead of a solid model. In many cases, point clouds can be generated from scanners or cameras in much less time than is required to produce a standard solid model using conventional 3D practices. In many design workflows, the final form of the machine is not known, so solid models must be created as digital prototypes or digital representations. But in many cases, the machine is already built and sitting on the factory floor. In this case, it is much easier and more efficient to utilize reality capture tools to generate a point cloud of the actual machine instead of developing a 3D solid model from hundreds of time-consuming manual measurements.
In this IMAGINiT Tricks tutorial, we will outline the process of generating a point cloud from photos using the new ReCap Photo service from Autodesk. The point cloud we generate will be used as an asset for the Autodesk Factory Design Suite.
Starting with the Pictures
The process starts off by taking many pictures of a machine from all directions and angles. It is important to include the entire machine in every picture, and to take pictures from both high and low angles. Every machine will be different, but in general it will require about 60 pictures to produce a decent point cloud.
There are several other criteria to keep in mind when photographing the machine, including:
- Collect pictures from all angles. Take pictures every 5 to 10 degrees as you circle the machine. Use a ladder to obtain images from higher positions as you circle the machine again.
- Avoid reflections and glare. Reflective surfaces are very difficult to stitch in the final scan.
- Create color contrast. The machine should stand out against the surrounding background.
- Use a consistent light source. The light source should remain constant in a single position. Do not use a flash.
- Photograph textured surfaces when possible. Textured surfaces are much easier to stitch in the final scan.
Taking the pictures is the hard part; once you have them, generating the point cloud is very easy. Simply log into your Autodesk 360 account and select the ReCap Photo option from your 360 Benefits.
Access Autodesk ReCap Photo from your Autodesk 360 account and begin generating the point cloud from your pictures.
Next, proceed to start a new project and upload the pictures. You will be notified via e-mail when the scan is complete. When your scan is finished, you can download it in various mesh and point cloud formats. For this example, we will download the RCS (ReCap Scan) file and open it with Autodesk ReCap.
Autodesk ReCap is used to clean up the point cloud scan and reorient the cloud for future use.
Autodesk ReCap is the tool we’ll use to interact with the point cloud scan. ReCap allows us to clean up the scan, easily removing any unnecessary points from the point cloud. In this example, the points that represent the floor were removed from the cloud. Autodesk ReCap also allows you to adjust the orientation of the cloud so the x, y, and z axes of the cloud are aligned to the machine and not arbitrarily set by the scan file.
Autodesk Inventor and Factory Design Suite
There are many methods of utilizing the point cloud in your design software. In this scenario, we will be using the point cloud to represent a factory asset. As we stated before, generating a 3D solid model of the machine will require many manual measurements and several hours of modeling time. Using the point cloud as the asset will save us quite a bit of time and will function just as well as the 3D model representing the machine and the space required for the asset.
The asset creation process starts by inserting the point cloud into an Inventor part file. The orientation of the point cloud, set in Autodesk ReCap, will be utilized when the cloud is inserted into Inventor. The original point cloud was generated in meters and needs to be scaled to the proper size. Inventor allows you to reorient the point cloud and apply the proper scale factor to the points. A single measurement of the actual machine is needed to determine the proper scale factor.
Point clouds can be oriented and scaled to suit the Inventor environment.
Publishing the Asset with a 2D Representation
To fully utilize the cloud as a factory asset, you need to add a 2D sketch showing the top view of the machine. This sketch is placed at the bottom of the point cloud, where the machine would rest on the floor. The 2D sketch contains a simple trace of the major design features of the machine’s top view.
From this point on, we will use the standard asset publishing process, with a few exceptions. The workplane containing the sketch will act as the landing surface and points on the sketch will be utilized as insertion points. When we publish the asset, we will make sure to select Publish Sketch as the 2D representation in the Asset Publish dialog.
Publishing the sketch is important for a couple of reasons. The sketch represents the point cloud asset in 2D environments, such as AutoCAD or Inventor drawing views. The sketch also provides a selection and gripping point, allowing you to easily move and manipulate the cloud asset in the factory layout assembly.
A 2D sketch depicting the top view of the machine is added to the point cloud prior to publishing.
Conclusion and Warnings
Now that you understand the point cloud asset method, you can begin to incorporate existing machinery as assets in your next factory layout. It is important to note that this method is not perfect, however, and there are a couple of pitfalls you need to be aware of. Some of the shortcomings are:
- No physical properties for point clouds. Point clouds do not supply physical properties such as volume and mass.
- No Navisworks translation. At the time of this article, point clouds do not translate from Inventor to Navisworks. The original clouds must be appended to the Navisworks scene separately.
- Low accuracy. Point clouds developed from photos do not have a high degree of accuracy. These clouds are just rough representations of the actual machine components.
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!