Does a furniture preview show texture and material detail?
A furniture preview shows texture at the level visible in the original product photo, adapted to the lighting in your room. The quality of the product image is the starting point. If the product photo shows the weave of a fabric clearly, the preview carries that detail into your room photo. If the product photo is low-resolution or shot from too far away, the texture will be similarly low-detail in the result.
The meaningful thing the preview adds beyond the product photo is how that texture reads under your room's specific light. Nubby linen that looks completely flat under studio lighting may show considerably more depth and character when placed in warm afternoon light from your west-facing window. A matte velvet that looks rich and dark in a showroom photo may feel lighter and more casual in a bright, south-facing room. Those shifts are real and the preview surfaces them.
Where the preview has limits: very fine material distinctions that require physical touch, like the exact softness difference between two fabrics, or the subtle sheen variation between two leathers described as nearly identical on the product page. For those distinctions, a sample swatch ordered from the retailer is still the most reliable test.
For the practical question of whether a textured fabric will look interesting or flat in your room, the preview gives a clear and useful answer. Try it free on your own photo.