First of all i want to say that your image doesn't look blurry to me at all, but of course everyone has his own taste for sharpness. It might be helpful if you could show one of your previous render which you consider sharp, so we can know what is your expectations. Anyway, if you look at the edges of the objects, they are all sharp, that means there's no problems with image filtering. You may want to check bitmap filtering, a.k.a. blurring in 3ds max. Check your textures in material editor and see what is blur set at - default is 1.0, but you may want to set it to 0.1 or even lower. You can use batch material edit script to edit settings on several materials/textures at once. And lastly, applying sharpening in post-production, or in Corona VFB also might help a great deal.
first of all, thank you so much for your time. but what you mentioned about textures and stuff are so basic in rendering which i always take care of them.
I mean it's like a high amount of denoise has been applied to the image which killed the details, but I didn't use denoise at all...
here you can see my work specially in interiors all detail are always sharp
https://www.behance.net/mohsen-hashemiI'm going through render element "sampling focus" to see if I can find the problem