Re: Flashing at joints when checking for conflict Hello; When modeling, enter the columns first along their entire height in one piece. Then with the divide command, divide from the points where you will join and define the combination. It seems that a problem occurred due to a situation in the modeling phase. In your project, when you delete all the data, enter a 9 m column first, then divide it into 2 from the appropriate point and enter the union, it does not give a conflict error. Conflict error is not a problem for analysis and design. It is a check that must be done from the drawings. If you only need the design of the project, you can continue with this model. However, if you need to get a drawing for manufacturing, as you know, you cannot send a printout to the printer in demo versions, you have to re-install the model as I said above. This time, enter the columns from their full length first. Good work.