HP consumer line computers are NOT intended for this kind of usage. They just won't cut it for long. Given the budget range you are looking at then a desktop-class processor is probably going to be the best cost-efficient option. I would suggest leveraging as much hyperthreading and cores you can use so hop on the LGA2011 platform if you can. It runs hotter than the LGA1150 platform, but given the work you are doing, you can use the CPU room and the additional memory capacity capabilities. Also, you are going to be running a dedicated graphics card, anyways, so no need for the onboard GPU of the other LGA1150 platform.
As I stated above, I'd highly recommend looking into the professional graphics cards. Real businesses and professionals doing 3D content design use real professional graphics cards for a reason. Again yes, they are more expensive, but they are specifically built for this kind of use, and they have the driver support behind it to provide unparalleled reliability and efficiency in these kinds of software. Will an nVidia Quadro card play Star Citizen better than a desktop class GTX 770? No, but it sure is going to be better at actually BUILDING the world of Star Citizen.
If possible, stick with the Samsung 840 Pro SSD over the Evo. The Evo SSD is still great and my recommendation for most general office users, but what you are doing is not general home or office usage, and the TLC memory in the Evo will not offer you the same longevity or performance as the MLC that is in the Pro SSD. Still, they do offer pretty similar performance on average, especially when you configure your system for using a SSD properly. I also agree with the recommendation for Western Digital Black drives for data. Great performers and great reliability. We use them in most of our custom builds.