Volume and orthomosaic

Hi,

Is it mandatory to process an orthomosaic previously any volume computation?

If yes, why is it so hardware ressources consumable to generate this orthomosaic?

Thank you for your answer,

Hi Thierry, 

The volume computation is based on the Digital Surface Model (DSM). The latter is generated during step 3. DSM, Orthomosaic and Index, so it is necessary to run step 3 before doing volume computations. Note: If you do not need the orthomosaic output, unchecking the creation of the orthomosaic output in the processing options should save some processing time: 
The hard disk is the most important component during step 3 processing, maybe you can check for some improvements there. This article shows which components are used in which step of the processing: https://support.pix4d.com/hc/en-us/articles/202559519 

If you would like to know more in detail how the volume computations work I can suggest this article from our knowledge base: https://support.pix4d.com/hc/en-us/articles/202559239

Hope this helps!