Import a Processed Point Cloud to Generate the Point Cloud Model and Configure the Trajectory

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In this workflow, you can import processed point cloud to generate a point cloud model and configure the trajectory.

Under the Import processed point cloud workflow in the target object editor, click Select, and set the target object name to enter the configuration process. The overall configuration process is shown in the figure below.

overview

  1. Import project information: Select the project, point cloud, and the Step port outputting pick points, and then the target object model can be generated automatically.

  2. Edit model: Edit the generated point cloud model, including the calibration of the object center point and configuration of the point cloud model, to ensure better performance of the 3D matching.

  3. Set trajectory: Create and adjust trajectories on the edited point cloud model.

  4. Set collision model (optional): Generate the collision model for collision detection during path planning.

The following sections provide detailed instructions on the configuration.

Import Project Information

To obtain information from the project, select the corresponding project, the Step port outputting the surface/edge point cloud in the project, the reference frame to define point cloud, and the Step port outputting the pick point. Then click Preview to view the point cloud model in the visualization area on the left.

When selecting the reference frame for defining the point cloud, ensure that it matches the reference frame of the scene point cloud used in the subsequent 3D matching Step.

Edit Point Cloud Model

The generated point cloud model should be edited for better performance in the subsequent 3D matching.

Edit Point Cloud

Remove Interference Point Cloud

If there are interference points around the point cloud model, you can remove the interference points by editing the point cloud. Refer to Edit Point Cloud for detailed instructions.

Select Feature Point Cloud

  • When making the edge point cloud model

    In applications, the target objects usually come in various poses, corresponding to different point clouds. Only the point cloud most representative of the edge feature of the target object should be extracted and retained in the point cloud model.

    The figure below shows the edge point cloud model of the tube. The tube is symmetrical and similar to a cylinder. On the lateral area of the cylinder, only the point cloud of the edges is retained. Meanwhile, to ensure accurate positioning of the ends of the tube, the point cloud of the edges of the two ends of the tube is retained.

    select feature round tube edge

    The table below shows the edge point clouds of the tube at different poses.

    Tube poses Edge point clouds (in yellow)

    select feature round tube pose 1

    select feature round tube edge 1

    select feature round tube pose 2

    select feature round tube edge 2

    select feature round tube pose 3

    select feature round tube edge 3

    If the target object (such as a sheet metal part) is asymmetrical, the edge point clouds from all viewing angles should be retained.

    select feature sheet metal parts edge

  • When making the surface point cloud model

    The surface point cloud model is critical in verifying the pose correctness and calculating the pose confidence. Therefore, it is recommended to use the complete surface point cloud of the target object when creating the surface point cloud model to ensure the validity. The figure below shows the surface point cloud model of the tube.

    select feature round tube surface

Calibrate Object Center Point

After an object center point is automatically calculated, you can calibrate it based on the actual target object in use. Select a calculation method under Calibrate center point by application, and click Start calculating to calibrate the object center point.

Method Description Operation Application Scenario

Re-calculate by using original center point

The default calculation method. Calculate the object center point according to the features of the target object and the original object center point.

Select Re-calculate by using original center point, and click the Start calculating button.

In general, this method can be used to calculate the center point of all target objects.

Calibrate to center of symmetry

Calculate the object center point according to the target object’s symmetry.
After calculating the symmetry of the current model, the object center point will be set to the center of symmetry.

Select Calibrate to center of symmetry and click the Start calculating button.

This method can be used to calculate the object center point when filtering matching results by target object symmetry.

Calibrate to center of feature

Calculate the object center point according to the selected Feature type and the set 3D ROI.

  1. Select the Feature type according to the geometric features of the object, and the tool will calculate the object center point according to the feature type.

  2. (Optional) Enable Use 3D ROI and select the geometric features on the target object with the 3D ROI.

  3. Click the Start calculating button.

Target objects with obvious geometric features
calibrate to center of feature example

Reset to Original Point Cloud

During editing, if the current point cloud result is unsatisfactory, click the [Reset button to undo all editing operations and restore the point cloud to its initial state when entering the "Edit model" step.

After resetting the point cloud, you need to recalculate the object center point and update the point cloud model configuration.

Configure Point Cloud Model

To better use the point cloud model in the subsequent 3D matching and enhance matching accuracy, the tool provides the following two options for configuring the point cloud model. You can enable the Configure point cloud model feature as needed.

Calculate Poses to Filter Matching Result

Once Calculate poses to filter matching result is enabled, more matching attempts will be made based on the settings to obtain matching results with higher confidence. However, more matching attempts will lead to longer processing time.

Two methods are available: Auto-calculate unlikely poses and Configure symmetry manually. In general, Auto-calculate unlikely poses is recommended. See the following for details.

Method Description Operation

Auto-calculate unlikely poses

Poses that may cause false matches will be calculated automatically. During the calculation process, a set of candidate poses is automatically generated based on equivalent or ambiguous poses that may arise due to the target object’s rotational symmetry about the Z-axis. In subsequent matches, poses that successfully match these poses will be considered unqualified and filtered out.

  1. ClickCalculate unlikely poses to calculate potentially mismatched poses.

  2. (Optional) If you think a pose in the list will not cause a false match, click the × icon to remove it from the list.

Note that the calculation results will not be automatically updated when the point cloud model is modified. If there are any modifications, please click "Calculate unlikely poses" again to update the results.

Configure symmetry manually

Calculate potentially mismatched poses based on the manually set parameters such as the Order of symmetry and Angle range. In subsequent matches, poses that successfully match these poses will be considered unqualified and filtered out.

Select the symmetry axis by referring to Rotational Symmetry of Target Objects, and then set the Order of symmetry and Angle range.

After the symmetry is set manually, the symmetry setting of the target object takes effect in the Coarse Matching, Fine Matching, and Extra Fine Matching (if enabled) processes in the 3D Matching Step.

When this feature is enabled, you should configure the relevant parameters in the subsequent matching Steps to activate the feature. See the following for details.

  • If the “3D Matching” Step is used, go to Adjust or Filter Poses from Coarse Matching  Select Strategy, and select Filter potentially false poses in the drop-down menu. This parameter will appear when the parameter tuning level is set to Advanced or Expert.

  • If the “3D Trajectory Recognition” Step is used, navigate to the “Target object selection and recognition” process, locate Adjust or filter poses from coarse matching  Select strategy, and select Filter potentially false poses. This parameter will appear when the Advanced mode switch is turned on.

Set Weight Template

During target object recognition, setting a weight template highlights key features of the target object, improving the accuracy of matching results. The weight template is typically used to distinguish target object orientation. The procedures to set a weight template are as follows.

A weight template can only be set when the Point cloud display settings is set to Display surface point cloud only.

  1. Click Edit template.

  2. In the visualization area, hold and press the right mouse button to select a part of the features on the target object. The selected part, i.e., the weight template, will be assigned more weight in the matching process.

    By holding Shift and the right mouse button together, you can set multiple weighted areas in a single point cloud model.
    set weight template

  3. Click Apply to complete setting the weight template.

For the configured weight template to take effect in the subsequent matching, go to the “Model Settings” parameter of the “3D Matching” Step, and select the model with properly set weight template. Then, go to “Pose Filtering” and enable Consider Weight in Result Verification. The “Consider Weight in Result Verification” parameter will appear after the “Parameter Tuning Level” is set to Expert.

Now the editing of the point cloud model is completed. You can click Next to set the trajectory for the point cloud model.

Set Trajectory

Create Trajectory

The tool provides two methods to create trajectories: Manual create and Automatic create.

In this workflow, Manual create is recommended to create trajectories on the point cloud model.

Create Trajectory Manually

After clicking Manual create in the "Set trajectory" workflow, you can enter its page. The detailed operation steps are as follows.

  1. Pick trajectory points.

    Hold Shift and right-click on the object to pick trajectory points. The tool automatically connects trajectory points into a trajectory.

    create trajectory manual

  2. Adjust trajectory points.

    The list on the right side of the visualization area shows created trajectory points. If trajectory points do not meet requirements, adjust them as follows.

    Operation Description

    Adjust trajectory point position and orientation

    Select the trajectory point, then adjust corresponding values in "Trajectory point settings" to adjust its position and orientation.

    Adjust trajectory point order

    Drag in the list to adjust trajectory point order.

    Add trajectory point

    ClickAdd button, and the tool adds a new trajectory point after the last trajectory point.

    Align trajectory points

    Select at least three trajectory points in the list, then click Auto-align. The Z-axis of selected points becomes perpendicular to the fitted plane of these points, and the X-axis points to the next trajectory point.

    Interpolate trajectory points

    If picked trajectory points are unevenly distributed, interpolate trajectory points to make the distribution more uniform.
    Select two trajectory points, set the "Max distance" parameter, and click Interpolate points. When the distance between the two points exceeds this value, the tool automatically inserts trajectory points between them, replacing other trajectory points between the selected points.

  3. Save trajectory.

    After creating trajectories, click Save and apply to save trajectories.

Create Trajectory Automatically

After clicking Automatic create in the "Set trajectory" workflow, you can enter its page. The detailed operation steps are as follows.

  1. Set the ROI.

    Click Edit  Add in sequence, and set the target area in the visualization area by selecting points where the trajectory is to be generated.

  2. Generate trajectories automatically.

    Click Generate trajectory, and the tool automatically generates trajectories.

  3. Adjust trajectory points.

    The trajectory line list shows generated trajectories. If needed, you can simplify and smooth trajectories by adjusting the following parameters.

    • Trajectory simplification

      You can simplify trajectories by adjusting the following parameters. By reducing the number of trajectory points, the trajectory shape is simplified while preserving the overall shape as much as possible. This is suitable for scenarios that require reduced trajectory complexity, such as reducing subsequent processing time and improving robot motion efficiency.

      Parameter Description

      Max deviation

      Maximum allowed deviation (H) when simplifying trajectories. The larger the value, the more points are reduced, but the trajectory shape may be distorted.

      Min distance to retain

      If the distance (Dis) between two trajectory points in the original trajectory is greater than this value, both points will be retained.

    • Trajectory smoothing

      You can smooth trajectories by adjusting the following parameters. Smoothing trajectory points reduces noise effects in the trajectory and generates a smoother trajectory. This is suitable for scenarios where trajectory points contain noise, improving trajectory smoothness and continuity.

      Parameter Description

      Gaussian sigma

      Controls smoothing intensity. The larger the value, the smoother the trajectory, but details may be lost.

      Smoothing radius

      The window size used for smoothing, determining the range of trajectory points participating in smoothing computation.

      Distance threshold

      Used to determine whether surrounding points of the point to be smoothed participate in smoothing computation. If the distance between the point to be smoothed and surrounding points exceeds this value, surrounding points do not participate in smoothing computation. It is recommended to use the default value.

  4. Save trajectory.

    After creating trajectories, click Save and apply to save trajectories.

Adjust Trajectory

After trajectories are created, you can adjust trajectories.

  • Adjust trajectory line

    After creating trajectories, if you need to offset a trajectory line by a certain distance along the Z-axis to better meet actual trajectory operation requirements, select a trajectory line in the trajectory list and set the Z-axis offset distance parameter.

  • Adjust trajectory point individually

    After selecting a trajectory point in the trajectory list, adjust corresponding values in the parameter settings area to adjust its position and orientation.

For other operations on trajectory adjustment, refer to Adjust Trajectory.

Preview Trajectory Effect

After trajectories are created, you can preview the positional relationship between the end tool and trajectories by following these steps.

  1. Ensure the Mech-Viz project is within the current solution.

    To ensure that the end tool information in Mech-Viz can be updated in the target object editor, refer to xref:viz-operation-guide:project-and-solution.adoc#export-project-to-solution[Mech-VizExport ProjectMech-Viz to Solution to move the project to the current solution.

  2. Add an end tool.

    Add an end tool and set the TCP in Mech-Viz.

  3. Preview and enable the tool.

    Once the end tool is added, the tool information will be automatically updated in the tool list within the target object editor. You can select a tool in the tool list according to actual needs, preview the positional relationship between trajectories and tools in actual trajectory operations in the visualization area (as shown below), or enable the end tool for actual trajectory operations.

    If you have modified the tool configurations in Mech-Viz, save the changes in Mech-Viz to update the tool list in the target object editor. In addition, enabling the corresponding tool for the trajectory in the target object editor is a prerequisite for successful simulation in Mech-Viz.
    configure picking example

Set Collision Model (Optional)

The collision model is a 3D virtual object used in collision detection for path planning. You can configure the following settings on the collision model according to the actual situation.

Set Collision Model

The current workflow supports two collision model generating modes. You can select the appropriate mode based on actual requirements. After selection, the tool automatically generates point cloud cubes for collision detection.

Generating mode Description Operation

Use STL model to generate point cloud cube

Low model accuracy, fast collision detection.

  1. Select the STL model.

    Click Select file, select an STL model, and use it to generate the point cloud cube. You can use the "Display collision model" feature to preview the generated collision model.

  2. Align models.

    Aligning the collision model with the point cloud model of the target object ensures effective collision detection. You can click Auto-align point cloud model and collision model to achieve the alignment with the point cloud model of the target object. If the auto-alignment result is not as expected, manually adjust the collision model pose.

Use point cloud model to generate point cloud cube

High model accuracy, slow collision detection.

After selecting this mode, the tool automatically generates a collision model from the current target object’s point cloud model. You can use the "Display collision model" feature to preview the generated collision model.

Configure Symmetry of Held Target Object

Rotational symmetry is the property of the target object that allows it to coincide with itself after rotating a certain angle around its axis of symmetry. When the “Waypoint type” is “Target object pose”, configuring the rotational symmetry can prevent the robot’s tool from unnecessary rotations while handling the target object. This increases the success rate of path planning and reduces the time required for path planning, allowing the robot to move more smoothly and swiftly.

Select the symmetry axis by referring to Rotational Symmetry of Target Objects, and then set the Order of symmetry and Angle range.

Now, the collision model settings are completed. Click Save to save the target object to Solution folder\resource\workobject_library. Then the target object can be used in subsequent 3D matching Steps.

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