Is it ok to model from another concept and how should I go about it?

Hello all, I am fairly new to environment design and I am looking to use a concept and model it out in Maya. I was wondering what is the proper way to contact people about this topic and what websites would be best to find pieces people want to be modeled? I would love to hear any experience you guys have on the topic and anywhere you found where there are good concepts. Also, is it good to show my environment design skill or is it better to work from a personal concept(I do not make concepts). My worry is I will find concepts that are not actually good so I wind up wasting time making something for a portfolio piece that looks terrible. Looking to get into the game's industry and mainly a modeler/lighting artist with texturing on the side. Anything helps