TL Helmert Transformation App Demo
1.7 هزار بار بازدید -
5 سال پیش
-
A seven-parameter similarity transformation calculator
A seven-parameter similarity transformation calculator in 3D space.
This App will allow you to compute a seven-parameter Helmert transformation inside AutoCad, use the computed matrix to transform AutoCad entities, save and load transformation settings to an XML file, display detailed transformation info, visualize transformation on the screen and adjust (turn on/off) individual parameters.
The seven parameters are:
Tx - Translation along the X axis
Ty - Translation along the Y axis
Tz - Translation along the Z axis
Rx - Rotation about the X axis
Ry - Rotation about the Y axis
Rz - Rotation about the Z axis
Scale - scaling factor
Workflow:
Start by defining a set of source/destination point pairs on the screen which will be used to compute a Helmert transformaion.
(TLHelmertNew command)
Carefully examine the output information produced and pay particular attention to the list of residuals to make sure there are no outliers.
(Note: with a small number of observations identifying possible outliers might be difficult)
The Helmert transformation will compute values for the 7 parameters such that the error function value is minimized. The error function is defined as the sum of squared distances between the transformed source point set and the destination point set. In an ideal case this number will be zero, resulting in a perfect match ie the source point set will exactly match the destination point set after transformation.
Once the transformation is computed it is automatically set as active/current and can be immediately used to transform autocad drawing entities using the TLHelmertTransformEntities command.
The app allows any combination of parameters to be turned on or off. For example you may want to prevent rotation along the X and Y axes by turning off the Rx and Ry transformation parameters, resulting in a 5 parameter Helmert transformation. This can be accomplished by issuing the TLHelmertEdit command. Another common scenario is to disallow scaling by forcing a scale factor of 1.
The TLHelmertSave and TLHelmertLoad commands allow you to store/retrieve transformations to/from an XML file. Note that the TLHelmertLoad command will replace the current/active transformation.
If/when things don't go as expected the app provides two additional commands to help troubleshoot transformation issues:
The TLHelmertInfo command prints detailed information about the current/active transformation inside the standard acad command window and the TLHelmertVisualize command draws all those numbers on the screen in the form of acad entities to help better visualize how the source point set maps to the destination point set
For additional information and to download the app please visit the Autodesk App Store:
https://apps.autodesk.com/ACD/en/Deta...
This App will allow you to compute a seven-parameter Helmert transformation inside AutoCad, use the computed matrix to transform AutoCad entities, save and load transformation settings to an XML file, display detailed transformation info, visualize transformation on the screen and adjust (turn on/off) individual parameters.
The seven parameters are:
Tx - Translation along the X axis
Ty - Translation along the Y axis
Tz - Translation along the Z axis
Rx - Rotation about the X axis
Ry - Rotation about the Y axis
Rz - Rotation about the Z axis
Scale - scaling factor
Workflow:
Start by defining a set of source/destination point pairs on the screen which will be used to compute a Helmert transformaion.
(TLHelmertNew command)
Carefully examine the output information produced and pay particular attention to the list of residuals to make sure there are no outliers.
(Note: with a small number of observations identifying possible outliers might be difficult)
The Helmert transformation will compute values for the 7 parameters such that the error function value is minimized. The error function is defined as the sum of squared distances between the transformed source point set and the destination point set. In an ideal case this number will be zero, resulting in a perfect match ie the source point set will exactly match the destination point set after transformation.
Once the transformation is computed it is automatically set as active/current and can be immediately used to transform autocad drawing entities using the TLHelmertTransformEntities command.
The app allows any combination of parameters to be turned on or off. For example you may want to prevent rotation along the X and Y axes by turning off the Rx and Ry transformation parameters, resulting in a 5 parameter Helmert transformation. This can be accomplished by issuing the TLHelmertEdit command. Another common scenario is to disallow scaling by forcing a scale factor of 1.
The TLHelmertSave and TLHelmertLoad commands allow you to store/retrieve transformations to/from an XML file. Note that the TLHelmertLoad command will replace the current/active transformation.
If/when things don't go as expected the app provides two additional commands to help troubleshoot transformation issues:
The TLHelmertInfo command prints detailed information about the current/active transformation inside the standard acad command window and the TLHelmertVisualize command draws all those numbers on the screen in the form of acad entities to help better visualize how the source point set maps to the destination point set
For additional information and to download the app please visit the Autodesk App Store:
https://apps.autodesk.com/ACD/en/Deta...
5 سال پیش
در تاریخ 1398/01/21 منتشر شده
است.
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