Unfortunately, there are very few websites that provide free 3D house plans. However, there are some websites where you can find modern house plans for a small fee. For example, Houseplans and The House Designers are two websites where you can find a large selection of modern house plans. Additionally, you can find some free modern house plans on websites such as Home Designing, Freshome, and ArchDaily.
House plans can be downloaded from many websites for a price tag or even free. But those free plans may not be a complete set of plans to ready start your project. But you are good to check it as long as they are free. I found a site which provides small house plans for free. Here's a link Modern House Plans. This site provides a complete set of plas with 3d renderings for free. It's worth to visit the site.
Here are some websites where you can get modern house plans for free:
Arch Daily
Pinterest
HomePlans
Houseplans
A collection of plans
Note that although some websites may offer free plans, they may not include all the details or be suitable for construction. It's best to consult with an architect or licensed contractor to make sure the plans you're using are accurate and up to code.
You can explore and download free contemporary house plans from House plans extensive collection.
Likewise, The Home Designers You can download a variety of contemporary house plans for free from this website. For access to the plans, you must first register.
There are several websites where you can download modern house plans for free, including:
The House Designers
ArchDaily
Tiny House Design
Houseplans.com
Dreamhomesource.com
HomeByMe
However, there are some websites where you can find modern house plans for a small fee. For example, Houseplans and The House Designers are two websites where you can find a large selection of modern house plans. Additionally, you can find some free modern house plans on websites such as Home Designing, Freshome, and ArchDaily