Photogrammetry and RTI

[kwagensonner]

Hello,

 

I recently started using photoscan in order to produce 3D models based on thousands of close-up photos. I wonder now whether (and I think I read so) it is possible to use RTI captures and Photoscan in order to create 3D models with the possibility to change the light angle. I happen to not be able to export the normals map in RTIviewer, which as far as I read is essential for this task. Does anyone have suggestions?

 

Best

Klaus

 

[GeorgeBevan]

You can simply export either point clouds or surfaces from Photoscan with surface normals to another software package, like Meshlab. You must have the normals on the exported 3D data to change light position. If the data is exported with normals, it is then trivial to then change the light-angle or the shader model (the Phong Model in Meshlab corresponds to the Specular Enhancement filter in RTIViewer). 

 

Mapping RTI normals onto 3D models generated by other processes, like photogrammetry, is rather more challenging and is discussed elsewhere in the forum. 

[cdschroer]

Thanks George - and I agree.

 

I'll add that an RTI isn't just a normal field.  It's a whole different way of collecting and processing data when compared to photogrammetry. The RTI file format is a different thing than either a single image or a 3D model.

 

We (and others) employ both techniques, and we find them to be complementary.  AS George notes there are other discussions of Photogrammetry and RTi on this forum.  Here's a topic with access to the file format information:

http://forums.culturalheritageimaging.org/index.php?/topic/389-where-can-i-find-the-file-format-specifications-for-rti-and-ptm/?hl=%2Bfile+%2Bformat

[kwagensonner]

Many thanks for the answers. I have done thousands of RTI images, mainly using domes. But I am rather new in matters of photogrammetry, so I was only wondering whether it is possible.