1. The aim of this project is to understand Photogrammetry. It is a means of reconstructing of a solid object as a 3D model capable of being 3D printed using a series of photographs in different angles.
2. Unlike dedicated scanning softwares like "SENSE" where specific equipment is required to be used to scan the object concerned. Photgrammetry uses basic equipment like a camera/ videocam to take a series of pictures/videos of any object. These are then used to reconstruct the object.
3DF ZEPHYR
3. There are various softwares available for undertaking 3D scanning and Photogrammetry. I have found 3DF Zephyr to be pretty user friendly, also it has a free version available without any time period. Hence, the software was chosen to understand the nuances of reconstruction of objects to develop 3D scanned models capable of being 3D printed.
4. The free version of the software can be easily downloaded for Windows as well as IOS softwares. It has a limitation of 50 photographs which will be processed to reconstruct the object.
5. Ideally, pictures of the object need to be taken from various angles rotating the camera gradually to develop a database of pictures of the object. These pictures are then imported into the software, and the type of object and pictures taken is indicated. FOr e.g. Human Face, Close Range.
6. The software based on the pictures taken will develop a 3d model of the scanned object, which can be corrected and exported. The software generally takes the data in a triangle section formed from the focus lens. The position of the camera are also shown in blue around the object in the software. Since, the software takes data from the photographs clicked, care must be taken to ensure a good constrast exists between the object of concern and the background when pictures are clicked. A method to ensure the software reconstruction is mainly focussed on the object of concern is the MAsquerade tool which is provided along with the software. It ensures the software doesnot confuse with the background and the reconstruction of the object is smooth.
7. In this assignment, the object of concern was a model of a warship made of wood and intricate carvings. Though, the limitation of 50 photographs were not sufficient to develop a smooth scanned model, it was used to understand the usage and limitations of the software. The camera was a DSLR which was fixed on a tripod and the object was rotated at fixed abgles, with the help of marked lines of the table on which it was placed. The setup of the exercise is as shown below.
MASQUERADE
8. It is tool to highlight the object and ensure the software doesnot confuse with the background. It is generally used to focus the scan in case of changing background which can be confused by the software giving poor scanned objects. In this tool the photogrphs taken are imported and the area of concerned is marked by a red brush and the background around the object is marked by a blue marker. The software focuses on the red area and ignores the background. The procedure is as shown below. This ensures that the software has good focussed pictures which are essential for the reconstruction.
Methodology
9. The object which has to be scanned to form a 3D model, is checked and the background for taking pictures should be kept at a contrast with the model. For this exercise the camera was kept on a tripod at a fixed place and the object of focus was rotated, at small angles to ensure 50 pictures as the 3DF Zephyr software used accepts a maximum of 50 photographs.
10. The photos are uploaded on the software. The background in the photos is neglected using the Masquerade tool as mentioned above. It results in more focus of the software to ensure development of a good rendering. The software captures the position of the camera angles with respect to the object. They are shown as a blue markings for understanding.
11. It case of symmetriacal objects it is observed that the camera positions are overlapped and we see one half of the object being developed. This can be duplicated post exporting in AUTOCAD MESHMIXER.
12. The model can be corrected and exported for 3D printing. The same methodology can be used for development of a 3D scan of simple objects to in turn 3D print objects.
