this is my first time printing, i used default setting (photon-s) and default supporting adding, but after slicing, it just court 3 hours, (supposed it should be 10 hours for such object) and I printed it, it only printed the support without the object on the top! any advice? Thanks.
I assume this is not an issue with the slicer, nor with the printer, but more with how you oriented your model. 1. 3 hours seems reasonable to me. It's only the height that counts, not the volume. 2. The reason why it estimated (and actually took) only 3 hours is also the reason why it failed. You oriented the part in a way that it takes the shortest time to finish but most probably fail.
Have a look at the slices of your model and try to imagine what's happening in your printer. First you print a bunch of support needles. Then, all of a sudden, you crate a HUGE face, which, at the beginning, is (as I suppose) 50 um thick. Thinner than a human hair. Sticking on your FEP film. Now the build plate retracts. Although the FEP is designed in a way that cured resin doesn't stick to it that much, you can imagine what happens, if you try to peel off a 50um film from it, holing on to the rest of the print only through some needle points. It breaks. It keeps sticking on your FEP. And all the following layers will, instead of creating your model, just stick to this layer sticking to the FEP. So, on the bottom of your vat you will now find a blob of cured resin. Search the internet (youtube) for "SLA orientation". And there you will see how to avoid this.