# Development of Communication Protocols between BIM Elements and 3D Concrete Printing
## 5 Analysis of Results
### Second Test: Controlled In Situ Speed Associated with Defined Point Spacing  
The code developed in Section 4 enables the user to enter a linear printing speed in meters per second (m/s). The purpose of this test is to verify the precision of the KUKATM  
Figure 6: (**a**) Element created in RevitTM; (**b**) element printing trajectory.  
Figure 7: (**a**) Element created in RevitTM; (**b**) element printing trajectory.  
robotic arm to carry out this speed in the field. The test consists, briefly, of entering speeds in the program and measuring in situ if these speeds are achieved.  
Previous studies have shown that robotic arms limit their maximum operating speed when they execute codes that require a series of points, as is the case with the code of this investigation. Thus, this test works with speeds that allow the robot to properly perform the printing process.  
Three different speeds were tested: 0.04 m/s, 0.06 m/s, and 0.08 m/s, with spacing between printing points of 12.5 mm, 25 mm, and 50 mm, respectively.  
To perform the measurements in the field, samples of 3D concrete printing were made, and the execution times were measured. Thus, based on the distance run by the robot, it was possible to calculate the speed in each attempt. As an example, a couple of images of the process are shown in Figure 8a,b, whereas Figure 8c shows other 3D concrete printed elements that were tested.  
Calculation of Error and Concordance in the In-Situ Controlled Speed Test in Terms of the Defined Spacing between Points  
Once the data have been obtained, it is important to demonstrate the significance of the experimental speed variations, for the theoretical or typed speed. Accordingly, there are two ways to quantify the measurement error: (a) by means of the absolute error (\(E\)), which corresponds to the difference between the average of the measured value \(X_{m}\) and the real measured value \(X_{r}\), so \(E=|\overline{X}_{m}-X_{r}|\); and (b) by means of the relative error (\(e\)), which corresponds to the quotient between the absolute error \(E\) and the average of the measured value \(X_{m}\), expressed as a percentage, or \(e\) (\(\%\)) \(=E/\overline{X}_{m}\)\(\cdot\)100. With the calculation of the relative error (\(e\)), it will be possible to verify the level of confidence in each measurement, i.e., \(n\) (\(\%\)) \(=100-e\) (\(\%\)).  
Furthermore, a match is found between the theoretical predictions of a hypothesis (model or theory) and the results of a measurement, when both values coincide within a range defined by the measurement error. The error \(E\) defines, around the value under study, an interval of uncertainty equal to twice the error (\(2E\)), that is, it indicates a zone within which the true value of the magnitude must be found. Thus, the lower limit (\(L_{lim}\)) and the upper limit (\(U_{lim}\)) of the uncertainty interval is given by \(L_{lim}=\overline{X}_{m}-E\) and \(U_{lim}=\overline{X}_{m}+E\). If both the theoretical or typed speed and the experimental speed measured in the field are within this range, the previously mentioned match between the theoretical predictions and the measurement results is achieved.