Pit Wall Mapping with Pix4D Obj’s and Textured Mesh.
Pix4D is a drone mapping software that has the ability to output an OBJ with Textured Mesh. This can then be opened up in Geovia Surpac and used for geological and geotechnical mapping. However there are some tricks to bring the image into Geovia Surpac.
When an OBJ with textured mesh is exported from Pix4D, it must not have any special characters or spaces in the file name. If it does, the 3 files (.mtl, obj, jpg) will all loose association with each other. If you cannot get the file exported with the correct naming convention then you can adjust the file names and the files themselves so they match up. The steps are outlined below.
1. Rename the obj file. In this example we have changed the file name to
2. Open the obj in an edit window and change the name of the mtl file to the same name as the obj
3. Rename the jpg to pix4d_texture
4. Rename the mtl fil to pix4d
5. Open up the mtl file in an edit window. Change the name so it matches step 3.
6. Drag and drop the OBJ and it should now have the associated image with the OBJ. You will notice that the OBJ is not in the correct co-ordinate system. There will however be an offset file with the exported data from Pix4D.
7. Digitize the geological contacts and structures on the obj and save the string file.
8. You can also use the Structural Suite located under the Database menu to create planes for the joints/faults seen on the obj.
9. Once the string has been saved, you can use the information from the offset file provided by Pix4D and
Graphics Layer Maths and adjust the coordinates by adding on the offset onto x,y,z.
10. Open up the data with the Point Cloud from Pix4D and the mapping will now be in the correct co-ordinate system.
If you have any questions please reach out to @KF or @AC or you can comment on the post below.
