hello i wanted to know how to convert contextcapture 3mx file to obj format
You can go back into ContextCapture and pick a different Production Format, in this case OBJ.
Just select the Reconstruction that produced the 3MX and click on Submit new production... , then select "OBJ wavefront format" in the Format/Options.
i think the real problem is it's hard to merge obj files to one
3mx file seams a single file ,Although index a lot of files
Open in Contextcapture Editor or Microstation and export as OBJ. You can change resolution using "Export Resolution" option under 3mx properties.
In CC editor (descartes too) when you export 3mx to obj you lose resolution. Changig export resolution in 3mx proprieties doesn't improve the result.
There is also mesh resolution setting in obj export.