It’s an old game anyway, maybe you can contact them and ask for resources:-)
So time for another update :
Now it is time for mines. There will be six resources in legends (and gold of course). Two main resources will be wood and stone.
Four special resources will be main ones for each castle. 2 for tech towns and 2 for magic towns. 5th town will not have one main resource, but will end up using all of them (like castle in h3).
For strategy it means that magic mines will be useless for tech towns, and going deeper into game mechanics hellium will be important for dwarves while oil for humans.
Same rules apply for magic towns.
Stone mine and helium mine :
Nest (egg mine) Mana node and Oil raffinery :
Gold mine, wood deposit and abandoned mine:
Another update on my work.
Some map objects :
Looks promising. Keep us updated
Thanks 
Work on map locations continues. BTW I’m surprised how many objects h3sod has. When playing I always had the impression it’s about 20 objects beside mines.
Another update on map objects A lot still left to do.
Another week another update
Wow, this game really looks a lot like heroes. It reminds me a little bit of Disciples as well. I couldn’t see how does it function but it seems it has the same resources.
Another update. Gates, quest guards and other situational objects , teleporters etc.
Almost all map objects are ready now. What’s still left is water objects, and map objects like arts, resources, pandoras.
Time for water objects
val-gaav, is there site of your project or git repo?
Sorry for the late reply, but I wanted to have some new stuff to show before posting.
No there is no webpage as I think it is better to not waste time on a webpage unless I have some beta or alpha version. Right now it is better to focus on graphics as there are still a lot of things left to do.
…
and no git repo as I work on this alone so there was no need for it.
So the only place for my project is this little topic, where I post updates.
This week update :
beginning of work on interface :
Looks like titanic work. These all objects were made from open-source 3D models?
Yes most are from 3d models, some from 2d. Some were heavily edited, some only slightly. About 10% of map objects is made from scratch by me (no modeling though as I am bad with 3d stuff),
As for sources license some are cc-0 some cc-by-sa.
Buttons for main menu (I’ve changed the design after some thought)
Now time for hero screen:
Primary skills, experience and potions icons will most likely be changed once I start to work on artifacts and secondary skills. Most likely because I think art style of those will be different…
Progress update :
Town window and hero exchange window.
Looking awesome 
I like this Interface. Look nice
Back from holidays so the work continues…
Build tree window in towns :
Could we use this graphics for heroes 3?