How can I read/transform the range images of the stanford bunny .ply-files?

As i read from stanford 3d scan

For all the Stanford models, alignment was done using a modified ICP algorithm, as described in this paper. These alignments are stored in ".conf" files, which list each range image in the model along with a translation and a quaternion rotation.

Here is the link to "this paper"

Edit: The two methods are called zippering and volmetric merging

As Ello mentioned, it is written at the stanford 3D repo:

For all the Stanford models, alignment was done using a modified ICP algorithm, as described in this paper. These alignments are stored in ".conf" files, which list each range image in the model along with a translation and a quaternion rotation.

But that is not enough to understand everything of this data file.

It is correct, that the first line:

camera -0.0172 -0.0936 -0.734  -0.0461723 0.970603 -0.235889 0.0124573

stores a good initial camera position and every other line starting with bmesh refers to a .ply-file, which stores a ranged image.

The transformation values are stored as followed:

transX transY transZ quatX quatY quatZ quatW

where trans... refers to a translation value and quat... refers to a value of the quaternion. Currently, I do not know, why it doesn't work with the quaternion rotation by itself, but by transforming it into a rotation matrix with the code of zipper the transformation is correct. Be aware, that the translation is stored first, but to get a correct transformation the rotation has to be done at the beginning and the translation afterwards.

My code snippet to read the files and transform it, is the following:

boost::math::quaternion<double> translation, quaternionRotation;
//Get Transformation
translationVec = glm::dvec4(lineData[2].toDouble(), lineData[3].toDouble(), lineData[4].toDouble(),0.0);
quaternionRotation = boost::math::quaternion<double>(lineData[8].toDouble(),lineData[5].toDouble(),lineData[6].toDouble(),lineData[7].toDouble());
//calculate the unit quaternion
double magnitude = std::sqrt(
      quaternionRotation.R_component_1()*quaternionRotation.R_component_1()+
      quaternionRotation.R_component_2()*quaternionRotation.R_component_2()+
      quaternionRotation.R_component_3()*quaternionRotation.R_component_3()+
      quaternionRotation.R_component_4()*quaternionRotation.R_component_4());
quaternionRotation /= magnitude;
rotationMat = this->quat_to_mat(quaternionRotation);

//do some file related stuff 
//...

//for each line: read the point data and transform it and store the point in a data array
pointData[j].x = stringPointData[0].toDouble();
pointData[j].y = stringPointData[1].toDouble();
pointData[j].z = stringPointData[2].toDouble();
//transform the curren point
glm::dvec4 curPoint =  glm::dvec4(pointData[j].x,pointData[j].y,pointData[j].z,1.0);
//first rotation
curPoint = rotationMat*curPoint;
//then translation
curPoint += translationVec;
//store the data in a data array
pointData[j].x = curPoint.x;
pointData[j].y = curPoint.y;
pointData[j].z = curPoint.z;

I know, that it's not the best one, but it works. Feel free to optimize it by yourself.