LDraw

LDraw is a comprehensive suite that is specially designed for LEGO aficionados who want to create 3D models, keep track of the current projects they completed or have a full list of the parts they required to complete their pending models.

Comes with a clean, well-structured and intuitive GUI

The setup is straightforward and simple, but it can take up to a few minutes depending on your PC resources and the size of the library you want to install. Upon launch, you are welcomed by a clear and user-friendly interface that is easy to navigate and understand, regardless of your computer skills.
While the application is solely a viewer, it is worth mentioning that you can use the LCAD rendering tool to create models from scratch or edit the ones you already have stored as images on your computer.  The editor allows to group pieces together, change their colors, add new parts and scripts to them, just to name a few of the possibilities.

Allows you to keep track of parts and create new models

It is worth mentioning that the application is capable of displaying a complete list of parts that you need to complete a full model. The feature can be especially useful if you obtained the model from other sources and you intend to build it yourself.
Not only does it provide you with the information about the number and code, but also the right hue and quantity, an option that can save you a lot of time in the long run. As a side note, in case you need more info about a part, then you can consider looking for it on developer's website or forum.

A useful utility for anyone who enjoys building with LEGO bricks

Regardless of whether you are looking for a parts organizer, need a flexible tool where you can draw the next model you intend to make or you just want to build LEGO models and scenes, Ldraw can come in handy.