CAD Model of Downpipe Connection

I need a CAD model for a downpipe shoe connection that transitions two square pipes into one single outlet. This is for a residential drainage system.

Requirements:
- Material: PVC
- Transition design from two square pipes to one outlet
- Approximate dimensions provided, but I am open to recommendations
- Should be suitable for residential drainage applications

Ideal Skills and Experience:
- Proficiency in CAD software
- Experience with plumbing or drainage system designs
- Knowledge of PVC material properties and fabrication

Please provide samples of previous similar work.