Is this modification legal?

[maxor_gan]

I am working on a farm map. I had downloaded several model as my plantations. For example GrapeVine by !!GORO!!. But I needed to modify this model, as in separating the "Grapes" geoset with the "Plants" geoset, each into 2 individual model, so that I can make my plants to "bear" fruits after planting for some times, and get rid of the fruits after harvesting. And I had enhanced the texture a lil to fit into my map's environment. I am not sure if this modifications is legal. I needed help on this.

And I couldn't contact the author for some time...he havent replied me though...

 

[Tr!KzZ]

I don't think it can be called illegal, but meh.

Just ask the creater of the model, if it's ok for him. Sometimes creators don't want to be asked about their models and give permission to everybody. So you can edit and modify their models to your own needs.
In another case you should contact the model creator and ask him for permission, and if you're allowed to do those changes. Some credits for the original creator would be fine, too.

I think it's ok when you tried to contact the author of the model and he's inactive for a long time.

Good luck with your map

(Don't worry you're doing nothing illegal, it's a question about respect and manners to ask for permission to edit the models)