Pcl: Set size of plane with `addPlane()` method in pcl_visualizer

[prajval10]

Your Environment

• Operating System and version: Ubuntu 18.04
• Compiler: gcc 7.3.0
• PCL Version: PCL1.9.0

Context

The addPlane() method for visualizing a plane either puts the plane in "some random location" or at a particular location if the user provides x,y,z value. However the size cannot be set/controlled by the user.

I can successfully add planes to my visualizer, however the size is extremely small. (note the other clouds are in millimeters). I saw related threads on PCL-users mailing list which suggest modifying the underlying VTK function.

For instance: the resulting plane in the attached figure is in white while other point-clouds are in red and blue.

Is there a way to control the size of the planes? Thanks!

[taketwo]

Plane visualization in PCL is rudimentary at best. Unfortunately it's not possible to specify neither size nor "shape" of the plane.

[prajval10]

Thanks @taketwo ! Any suggestions on how to modify the method to specify size, before I close this issue?

[taketwo]

Under the hood, addPlane() creates a VTK data source object, generates a VTK dataset, and adds it to the visualizer. You can implement these steps yourself and have full control over the generated dataset.

Specifically, create a data source (vtkPlaneSource in this case):

vtkSmartPointer<vtkPlaneSource> plane = vtkSmartPointer<vtkPlaneSource>::New ();

Then you need to configure the source. See the available functions here. You'll need to change normal and center to position the plane and point1/point2 to scale it along axes. Finally, you need to generate data and add it to the visualizer:

plane->Update ();
visualizer.addModelFromPolyData (plane->GetOutput (), "actor-id");

[prajval10]

Thanks again @taketwo, I managed to configure the addPlane() and the source as you suggested.

bool addPlane (const pcl::ModelCoefficients &coefficients, double x, double y, double z, double *point1, double *point2, const std::string &id = "plane", int viewport = 0);

vtkSmartPointer<vtkDataSet> pcl::visualization::createPlane(const pcl::ModelCoefficients &coefficients, double x, double y, double z, double *point1, double *point2)
{
    vtkSmartPointer<vtkPlaneSource> plane = vtkSmartPointer<vtkPlaneSource>::New();


    double norm_sqr = 1.0 / (coefficients.values[0] * coefficients.values[0] +
        coefficients.values[1] * coefficients.values[1] +
        coefficients.values[2] * coefficients.values[2]);

    plane->SetNormal(coefficients.values[0], coefficients.values[1], coefficients.values[2]);
    double t = x * coefficients.values[0] + y * coefficients.values[1] + z * coefficients.values[2] + coefficients.values[3];
    x -= coefficients.values[0] * t * norm_sqr;
    y -= coefficients.values[1] * t * norm_sqr;
    z -= coefficients.values[2] * t * norm_sqr;

    plane->SetOrigin(x, y, z);
    plane->SetPoint1(point1);
    plane->SetPoint2(point2);

    plane->Update();

    return (plane->GetOutput());
}

I'm not sure how to specify the point1 and point2 accordingly to scale the plane.

[taketwo]

Disclaimer: I've never actually used this plane data source. I'd suggest to look at the default values of these points (specified here):

  this->Point1[0] = 0.5;
  this->Point1[1] = -0.5;
  this->Point1[2] = 0.0;

  this->Point2[0] = -0.5;
  this->Point2[1] = 0.5;
  this->Point2[2] = 0.0;

and try to play around with them.

[prajval10]

Got it working! Thanks. :rocket:

[themightyoarfish]

Please share your code, this will be useful for others!

[prajval10]

Hi @themightyoarfish, the related code is described here: https://github.com/PointCloudLibrary/pcl/issues/2938#issuecomment-474863560

[themightyoarfish]

So you simply used larger values for the Point1 and Point2 properties and that scales the plane? I suppose that could be merged to PCL then.

[prajval10]

As far as I remember, yes.

[evinpinar]

Thanks for the code provided @prajval10, but how is it exactly used? Can I somehow add this externally, without modifying the pcl source code?

[themightyoarfish]

No you'll need to modify PCL code. I tried adding the changes to the functions creatig the Plane, but it didn't seem to have any effect. I probably did something wrong.

On 28 July 2020 17:01:43 CEST, "Evin Pınar Örnek" [e-mail] wrote:

Thanks for the code provided @prajval10, but how is it exactly used?
Can I somehow add this externally, without modifying the pcl source
code?

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[dopeboy]

In case it's helpful to anyone, @Marcus-Davi has written a function that does it all in one go. I didn't need to edit PCL source code. He has commented out some parts but I tried them and it works great - https://github.com/Marcus-Davi/Cpp-PCL/blob/243b6d494d424677dfa3319ab2bb37a7d5572e21/src/plane.cpp