Create a DTM after classify dense cloud on 4 separate chunk

[tuffi]

Hi,

I am workink on a quite big project, after aligment I divided the project in 4 different chunk to perform dense cloud generation.

Now I tring to merge chunk to generate DSM and DTm but..at 70% of the process..my pc have some problems.

i think that I can generate DSM for the 4 chunk than export and mosaic all DSM with ERDAS Image than I can reimport DSS on a merged chunk but without merging dense cloud and then generate the orthophoto.

Then I need also DTM and countour lines. I think to proceed on the same way..classify the separate dense cloud, generate DTM, mosaic all DTM in ERDAS and maybe generate countour line in ArcGIS.

my question is: Classification process in a full dataset after merging or classification on 4 different chunk results in the same datas or not? There is some statistical process that involves the full dataset at the same time?

Thank you

Emanuele