Connecting the Point Cloud

The connection of the point cloud takes place in the DICAM, the free construction.

position and the icon bar

• Create New Item 001 in Project

We create a new project and position. A specific template is not required. In the Free Design model area, we add the icons of the point cloud (function 1 – 7 – 3) to the icon bar, if not available.

Connect Point Cloud

Modellbereich DICAM

We open the dialog to connect the point cloud. Either via the new icon or the function from the menu.

• 1-2-05 "Connect point cloud"

• Use the browser button to select the point cloud "Treppenhaus.e57" in the unzipped folder

The transformation values are automatically determined in order to place the center of the source file on the origin of the Dietrich's project.

The number of points in the source file is displayed. In our file, just over 8 million.

Align filters

By selecting a filter, the number of points can be reduced. For such a small file as the sample file, this is not mandatory. However, we want to choose the process here that is also practicable for very large files.

• We choose the filter: Orientation cell 5cm

• Open Filter Setting for Editing

• If 1 is not yet entered, then enter it in the field before "Merge cell to point"

We'll only use the "Merge Points to Cell" filter. To use it, we enter a "1" in front, which indicates the order in which the filters pass.

This filter combines all points that lie in a cube with the specified edge length / cell size into one. Roughly simplified, we get one point every 5cm with this setting.

This reduction of the points allows the point cloud to be quickly aligned and clipped (cropped).

For larger projects, this value should be set larger. For example, 10cm, see saved setting "Alignment Cell 10cm" or even larger.

The other filters are rather rare to use. They can be used to filter out statistical outliers and individual outliers. This calculation is extremely time-consuming, but offers good results for scans with glitches in which there are implausible points.

• Filter dialog box confirm with "Ok"

• Set all reductions to 0 (if values are entered here)

• Button "Reduce Point Cloud (ClipBox) and Apply Filter"

By reducing it to 0, we get the complete geometric point cloud. By clicking on the button selected afterwards, we start the calculation.

The 6 scans of the e57 file are read in and the filters are applied. This process can take several minutes, depending on the size of the file, the settings of the filters, and the hardware. This will be displayed in the progress window. After the run, we see the result of our filter setting below. The number of points through Clip Box is unchanged because we didn't use clipping. The "Orientation Cell 5cm" filter has reduced the points to about 123,500.

• We close the "Connect point cloud" window with OK and can view the reduced point cloud in the free construction.

Transformation

• 9-1-2 "Basic View" to get into the top view

In the top view, it can be seen that the alignment is not yet usable.

As in the picture below, the orientation should look like in the end. The upper edge of the finished floor of the ground floor should correspond to the height of 0.00.

Transformation by Rotation Angle Z

To make the alignment, we switch again to the dialog for connecting the point cloud.

• 1-2-05" Connect point cloud

In the first step, we want to define the X-direction of the point cloud in the program. To do this, the point cloud must be rotated around the Z-axis.

• Click on "Measure" button behind "Transformation Rot.winkel Z:"

With this function, we can cut out a horizontal slice from the point cloud to determine the orientation more easily. The values can be entered here or accessed in the page view.

• "Measure" button to grab the values

• Choose two points to get a disc with a thickness of about 1m

• Confirm the excerpt with "Ok"

After confirming the cutout, we determine the orientation.

• Select point 1 and point 2 that should correspond to the X-axis

These points should be as far apart as possible to compensate for inaccuracies caused by the selected points.

We get back to the "Connect Point Cloud" dialog box. The angle of about -13 degrees is now in the corresponding field.

If an alignment according to the Y-direction or any known angle is desired, this can simply be added up here. The calculator is also available here.

In the background, we can already see the rotated point cloud.

Transformation in the X and Y directions

We stay in the dialogue, followed by the 2nd step, the shift in X and Y direction.

• "Measure" button at "Transformation Position X"

We get back into the dialog for cutting out a horizontal slice, as in determining the rotation around Z.

The values from the rotation are still stored and we can take them over with OK, or enter them again or grab them.

• Confirm values with "Ok"

A window will appear again explaining the next queries. First, the reference point in the structure is queried, then the points of the point cloud in X and Y, which should correspond to this point in the structure.

• Mouse-Right to select the origin 0, 0 in the building

• Select point of the point cloud that corresponds to the X value of the building reference point

• Select point of the point cloud that corresponds to the Y-value of the building reference point

Transformation in the Z-direction

We close the dialogue and look at the result in DICAM.

• Close dialog with "Ok"

• 9-1-4 "View" to view the result from the side

Here it is visible that the origin is still above OKFF EG.

Again, we can cut a slice out of the point cloud to determine the point. To determine the height, it is a vertical disk. For this reason, the direction of intersection is also queried for this determination. You can choose between the X and Y directions.

• 1-2-05" Connect point cloud

• "Measure" button at "Transformation Position Z"

• Select cutting direction X

• Two points above the stairs

The following is an explanation of the next queries. As a reference point in the building, we select the origin by clicking the right mouse button. Then we use the mouse to grab a point in the left area of the ground floor.

• Mouse-Right for Origin

• Select point in the left area of the ground floor

The transformation is thus complete.

Scenes

After a review in DICAM, we determine the correct alignment of the point cloud in the structure. We would like to save this intermediate status as a result. We are talking about a scene here.

Especially with larger point clouds, it makes sense to have different sub-areas available later as individual scenes. This scene can then always be used for creation. Scenes are stored in the directory of the source file, they can also have a significant file size depending on the number of points. The scenes can also be loaded without an existing source file, which makes it easier to pass on the point cloud to other Dietrich's users. Without a source file, no changes can be made to the scene.

The loading of a scene takes place without calculations and thus works without loss of time. When the project is closed, the last state is saved as a temporary scene, so that the last state is always available without calculation.

• 1-2-05 "Connect point cloud"

• "Save Scene" function

Saved scenes can be loaded using the "Apply Saved Scenes" function.

Clipping the point cloud

By clipping, the point cloud can be geometrically reduced, i.e. cut to size. For the reduction, we have the three main axes X, Y and Z at our disposal. If both clipbox boundaries are set to zero, this direction will not be reduced.

We want to choose the area of the stairs from the ground floor to the upper floor. The values can be re-entered here or conveniently accessed via the buttons.

• "Measure" button to grab the points for the reduction from X to X

• Select X-points to the left and right of the stairs

• "Measure" button to pick up the points for the reduction from Y to Y

• Select Y-points below and above the stairs

The view automatically jumps to the top view. The order is arbitrary, both the minimum and the maximum can be selected.

Clipping in Z "Reduction of the point cloud from Z to Z" is done in the same way. The view switches to the front view (ZoX).

• "Measure" button to pick up the points for the reduction from Y to Y

Here it is difficult to pick up the corresponding point on the ground floor floor.

• Select a nearby point

• Correct the value in the mask to 0.1, which corresponds to the point on the floor

To see the result in detail, we change the filter setting to "Detail Cell 5mm".

• Filter settings on "Detail Cell 5mm"

• "Reduce Point Cloud (Clipbox) and Apply Filter

After checking in DICAM, we save this scene under "Detail Stairs".

• Close the dialog with "Ok", check it in DICAM and then connect it in the point cloud Save the scene as "Detail_Treppe"

Unconnect to point cloud

The point cloud can be detached again by checking the box for connecting the point cloud. In front of the path of the e57 file you will find this checkmark, which will detach the point cloud from the project.

The fastest way to reconnect is to take over a saved scene, as no new calculation is required in this case.