Anyone recommend any shed design tools?

[Adsibob]

I would like to design and build an L shaped shed that also has an outdoor covered area for log storage/seasoning. The roof will be flat, measuring 2.5m in height on one side and about 2.2m on the other side. I have a basic idea in mind, and have found lots of online shed design templates where one can tweak existing designs and convert into cutting plans, but none appear to offer the kind of L shaped shed I want. 
Anyone have any recommendations for online tools that might be flexible enough for this, or shall I not bother with that and just design it from scratch. If from scratch, are there any rules/basic principles/resources people can recommend?

I want either a painted finish or natural wood, depending on cost.

[Nickfromwales]

I beefed up the roof joists of mine to give a 900mm cantilevered projection to the side ( gate off pavement to access path between shed / house ) and ‘front’ and changed to clear roofing sheets, eg to allow light through but also be reasonably protected from rain.

Worked a treat. 
 

Use the software to create 2 sheds and just Frankenstein the cutting list to produce what you want? 

[Russdl]

1 hour ago, Adsibob said:

I would like to design and build an L shaped shed that also has an outdoor covered area for log storage/seasoning.

If you have a bit of spare time use Sketchup. It’s not that tricky when you get into it. YouTube will help. 
 

Model the shed with standard sized OSB, ply or whatever you plan to use. 

[Onoff]