My team encountered an error that we cannot solve. We developed our application using Java, also some scripts written in Jython (scripts edited in HEC-DSS as shown in the given Documentation). Our application consists of 4 sliders that vary those 3 Optimization Parameters ( Curve Number, Recession Constant and Snyder Lag),the last slider varies the Precipitation Percentage ( between 80% and 120% from the initial values) and of course the two plottings of Hyetograph and Hidrograph.

And it works like this : We run our application with HEC-HMS closed because we use scripts that manipulate comand prompt to lunch HEC-HMS. We can either vary one optimization parameter or all three as desired and, without varying the Precipitation first, after running the application the result is the two graphics ( Hydrographic and Hyetographic) plotted properly. The problem occurs when we vary the Optimization parameters along with the Precipitation percentage:

• ·     As we were varying all the parameters and we Ran our application the Hyetograph was plotted accordingly however the Hidrograph stayed the same as nothing changed with the Precipitation
  
• ·         At this point, after many times questioning the functionality of our app, we decided to open HEC-HMS, and when we moved to Time Series to Gages Table we could definitely see that the new parameters values for precipitation were updated in the Table but the Results of the Simulation Run1 did not indicate a change in the Hidrograph, as though nothing happened.
  
• ·         We then went for Computing Run1 and just after manually handling the situation we could get the Hidrograph changed according to the new Precipitation values existing in HEC-HMS.
  
• ·         We then closed HEC-HMS, and we ran one more time our Application (SECOND TIME), varying again the Precipitation parameters and surprisingly it worked ! We could not give ourselves an explanation about what really happened and again we Ran one more time ( THIRD TIME) our App, this time it didn't work - the Hidrograph stayed the same as the last run of the app.
  

So there are some issues we can emphasize at this stage :

The app works only when we vary the Optimization Parameters ( and it works properly ) but then when we vary also the Precipitation Percentage the Hidrograph does not plot properly. We went through many log files, background folders that could explain what really happens in the background, also CMD windows that pop up when our app is running, all these steps done assisted by Catalin,  and we think that it is not enough to give the new Precipitation Percentage to HEC-HMS ( received by HEC when we run our App) because once we vary the Precipitation Percentage our script that should make HEC-HMS to run the Simulation does not Compute Run 1 anymore. We think that somehow HEC-HMS skips the Computation of Run 1.

We are stuck here right now and so far we couldn't find anything.

Are there any files that can help us solve this, any log files, anything that could give us a better view on what happens in the background of HEC-HMS after running a simulation ?

If any other information is needed to better understand this matter we will gladly provide.