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Desktop Mapper - Processed Steps 1 & 3, now no access to Orthomosaics


I’m new to Pix4d and am on the trial version but experienced something odd that I can’t seem to get around and was hoping for some help. 

I processed a map with steps 1 and 3 selected as I didn’t need the point cloud at the beginning. The processing finished just fine, got my quality report and could see the preview of my ortho and DSM. Then, with the “Mosaic Editor” button no longer grey, I was about to export my orthomosaic when I got pulled away. When I came back I was curious about processing just the option for “2. Point Cloud and Mesh,” so I clicked on the checkbox next to the “2”. When I did that everything got weird: The 3rd option (which was previously green) was now red. The Mosaic Editor was now greyed out again and I had no ability to create my ortho image. Now, when I select the checkbox next to the 3rd step, I get a warning telling me that if I re-process the data that already exists will be overwritten. 

However, I have clicked on every option and searched around, and can’t seem to find how to create to my ortho image without reprocessing. Am I missing something?

Thank you in advance for your help!

Hello! :slight_smile:

Yes, it is possible to process Step 3_ _without processing Step 2 and still obtain the orthomosaic and the DSM. However, it is not recommended as the results will be of low quality.

Here comes the explanation of the low resolution of the outputs:

  • The orthomosaic is generated using the DSM (2.5D Digital Surface Model)
  • The DSM however, is generating using the densified point cloud which you obtain after processing step 2.

If you skip the Step 2, the DSM will be based on ATM (Automatic Tie Points) which are generated during step 1.

As the number of the ATPs is much lower than the number of the points in the densified point cloud what we get is much less information about the terrain, therefore, products are more inaccurate and incomplete. 

Each of the steps is strongly related to each other and one change of the previous steps automatically requires a change of the subsequent outputs. So once you marked Step 2 to be processed, Step 3 became red to remain you that DSM, Orthomosiac_ _and Index are still for

The software asks for confirmation in order to overwrite the outputs in your Result Folder to prevent you from losing the data as the new outputs won’t be saved under different names.