# Merging Completely Processed Subprojects - Need to re-process?

**URL:** <https://community.pix4d.com/t/merging-completely-processed-subprojects-need-to-re-process/7026>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [August 11, 2018, 1:31am UTC](https://community.pix4d.com/t/merging-completely-processed-subprojects-need-to-re-process/7026 "2018-08-11T01:31:22Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Kenji\_Salmoiraghi](https://avatars.discourse-cdn.com/v4/letter/k/d07c76/32.png) [@Kenji\_Salmoiraghi](https://community.pix4d.com/u/Kenji_Salmoiraghi)\
**Post date:** [August 11, 2018, 1:31am UTC](https://community.pix4d.com/t/merging-completely-processed-subprojects-need-to-re-process/7026/1 "2018-08-11T01:31:22Z")

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I have a large project (8,000 images) that has been split into 15 sub projects of roughly 500 images each.&nbsp; They have individually been processed completely (steps 1,2, and 3).

When doing a test merge of 4 of these subprojects, they only show step 1 “Initial Processing” as being processed once merged together.&nbsp; Is it necessary to reprocess steps 2 and 3 for the merged project?&nbsp; Is there a way to merge the subprojects and retain the processing in entirety?

The reason for splitting into such so many subprojects is that I don’t think my computer system can handle the processing of such a large project although it meets the minimun requirments of16 GB RAM, 80 GB Hard Drive space.

Is there any way to avoid processing the entire project as one?

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Thanks

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**Author:** ![Julie\_Pichon](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/julie_pichon/32/592_2.png) [@Julie\_Pichon](https://community.pix4d.com/u/Julie_Pichon)\
**Post date:** [August 13, 2018, 8:19am UTC](https://community.pix4d.com/t/merging-completely-processed-subprojects-need-to-re-process/7026/2 "2018-08-13T08:19:50Z")

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Hi Kenji,

The merging workflow ([learn more](https://support.pix4d.com/hc/en-us/articles/202558529)) consists in merging the results of step 1 only that you generated separately for each sub-projects. In other words, the results of steps 2 and 3 are lost and you will anyway have to process steps 2 and 3 for the final merged project.

Note that big projects require many computational resources but also the outputs are significantly large, meaning that sharing and using them in other third-party software or application will probably be a problem. This is something important to take into consideration.

An alternative would be to keep the results separated for each sub-projects, meaning that you will obtain several outputs, and use common GCPs to ensure they align correctly.

Hope it helps!

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