How can I export my band math result out as a tif or any image?

Dear all,
I have tried to build a ratio index named RBI with the band math tool using L2A S2A data. The RBI was successfully created and correctly displayed in Snap. And I resampled the L2A to 10m, and subset the many of its needless bands and export to a Geotiff image. All the kept bands were correctly output , but my RBI wasn’t output at all.
Anyone ever face this problem?
Looking forward to your help.

if you apply band maths you need to uncheck the “virtual band” option so SNAP creates an actual product.
Then save your product (File > Save) and it will be included in subsequent outputs.


Thank you very much. But how should I un check the virtual bands? c.z. the band math require a target file and it is the parent file? Or should I rename one? Let me try.

Have you seen the Tutorials?
There is one dedicated for Band Math:

Thanks. Though I can’t watch the tutorial , problem is solved now. By uncheck the “virtual (save expression only, don’t store data)” on the bandmath interface.