I am wondering if VO-SWMM has the capability to estimate catchment areas of each storm? If so, how would I access this feature? - Visual OTTHYMO

There is a tool in VOSWMM to extract the area of a subcatchment. To do so, you can do the following steps.
1- open VOSWMM and click on the tab “Map”

2- click on “Add Layer”
3- select the layer that you have.
You can see that VOSWMM accepts a lot of formats.

5- select “subcatchment” from the Tool Box and draw your desired subcatchment.

You can see the area of your subcatchment on the right side under properties.
If you have a shapefile and you don’t want to draw a new shape you can right-click on the existing shape and use “Update Geometry Parameter” to update the area value.

I have created an IDF group and would like to create various AES design storms using the group. I am easily able to generate the 1 hr storm but I am not sure how to make the 12 hr Storm. I do not have the option to change the Mass Curve to the 12 hr curve

The difference between TIMP and XIPM