merge two projects in PIX4Dmatic

Hello ,
I am reaching out to you as I recently began learning and utilizing Pix4Dmatic software for my mapping and surveying projects. While navigating through the software, I encountered a challenge that I am hoping you could help me with, along with a couple of related queries.

My primary issue revolves around merging multiple projects in Pix4Dmatic. Specifically, I have been attempting to merge new projects, where tentative points have been set, into a final project. However, despite ensuring that all projects are set to the same coordinate system before merging, the final output suggests that the projects are not aligned within the same project area or coordinate system. Additionally, my version of Pix4Dmatic appears to lack a specific window or feature that facilitates the merging of new projects, further complicating the process.

Furthermore, I am eager to learn more about Ground Control Points (GCPs) and tie points within the Pix4Dmatic environment. While I understand their significance in achieving accurate georeferencing and alignment, I would appreciate further clarification on how to effectively utilize them within my projects.
Thank you

Hi @ebaa289

Can you tell us which version of the software you have been using? You can see the version in the bottom left corner of the welcome view. I’d recommend to download version 1.58.1 here: Download Pix4D software

Also, could you show some screenshots of the error messages you get? or of the resulting project you have? This will help us understand the context of your project better.

You do have overlap between the projects you’ve merged, right?

As for the merging process, you can find more info here:

Not sure if you read this article already, but that’s a good place to start:


Dear Mr.Pierangelo

Thank you very much for your prompt response .
The version of the software is 1.47.1 , I will try to update into the mentioned version.
Yes I do have overlap between the projects after merged. ( i attached screenshots ).

Dear @ebaa289

It looks like your subprojects are not located at the same spot (i.e. either by having the same GCPs in both projects, by having two RTK/PPK projects,…). In such cases, you need to create min 3 MTPs in each project at the same spot. These will be used for the “register” step in the merge procedure, so that they end up in the same spot. More details in the article I linked above.

Thank you very much , it worked . but I faced other issues , after merging the (mesh) the images is not appear or the visibility is not clear like as individual projects ( No Orthomosaic after merging) . any advices to avoid and improve this ?
this image after clabration and before add the GCPs and MTP

this image is after adding the GCPs and MTP , i did reoptimization , the quailty became not good.

here after merging , no overpaling but , but images is not appear or the visibility is not clear like as individual projects ( No Orthomosaic after merging)

Project_ 2024-02-14-14-01-15-quality_report_compressed (1).pdf (3.7 MB)
Project_2024-02-14-13-59-50-quality_report_compressed.pdf (2.8 MB)
Project_2024-02-14-13-59-50 (merge with 15)-quality_report_11zon.pdf (199.7 KB)

@ebaa289 the merging currently only merges the Automatic Tie Points (ATPs), which is the result you get after the “Calibrate” step, this explains why there is no ortho, no mesh, no dense, after you merged. You need to process these in the merged project, so that it takes the merged calibration outputs as input.

If you reoptimize, only the ATPs get reoptimized, all other already processed outputs are “Outdated”, this explains why there are orange circles next to the other outputs in the content panel.

In summary, you need to process the densification, mesh, dsm, ortho once the project was merged, or reoptimized. This is meant so that you can ensure the quality of the calibration first, which will lead to more accurate results in the rest of the process.