gtx 1060 or which graphics card is better for unreal engine

I want to start work with unreal engine for architectural visualization. So I want to buy gtx 1060 .My question is gtx 1060 will be better for this type of work .or any other gpu ? please suggest me.

A 1060 will do fine and is probably the best value for money video card you can get right now

Depends on how many polygons you want to do on screen.
High resolution textures to render realistic scenes in UE4 do not impact performance as much as you would think.
If you’re planning on doing modern minimalist designs, then you do not need a powerful graphics card and a GTX 1060 or lesser is fine.
However, if you’re doing something like a Cathedral or Skyscraper in 1:1 detail for a construction company, then you’ll want to get a business class graphics card like a Nvidia Quadro.
Before you make a purchase decision, why not download some project files and work with what you have now to gauge what you may need later?
Also, graphics memory plays an important role on how many polygons can be rendered in real time on screen like LOD and such (always get more of it).

AAA Games on PS4 and PS4 Pro can demonstrate some great architectural visualization and run on 1 Teraflops and 4 Teraflops respectively.

Intel HD 530 Integrated Graphics = 1 Teraflops
GTX 1050 = 2 Teraflops
GTX 1060 = 4 Teraflops
GTX 1070 = 6.5 Teraflops
GTX 1080 = 9 Teraflops
GTX 1080Ti/Titan = 12 Teraflops

A better graphics card doesn’t mean more polygons on screen.

The amount of vram is a big concern. Particularly when working with high resolution textures and applications like Substance Painter. Or working a game targeting a high resolution (1440p or 4k) display.
But yes, texture resolution doesn’t have a performance impact outside of how much vram is being used and the memory bandwidth.

The bigger the project, the more bleeding edge tech used, and more dynamic the project is, the more likely you’ll need a more powerful GPU.

The only reason I’d suggest getting a Quadro is for CAD work or an applications that specifically requires it. Real time Architectural Visualization work using UE4 does not benefit from a Quardo, and it’s a huge waste of money and you’ll likely get worse performance.

Teraflops isn’t the best way to compare GPUs, unless they are being used to compare very similar chips. It’s a decent rough estimate, but don’t directly compare the TFLOPS on an AMD card to an Nvidia card, to a 3 generation old Nvidia card, to the PS4 Pro, because at that point, TFLOPS are a meaningless tech spec. Like the GTX 1050 is at least 3-4x faster than the HD 530 in games.