If you want to create LEGO models with a simple CAD program that is straightforward and doesn't consume your computer's resources, we recommend LeoCAD. It's one of those tools that turn a very complicated task into something universal. The platform boasts more than 6,000 virtual LEGO model pieces, so you can let your creativity run wild.
Once you download and install the program from its official page, you'll see the LEGO pieces on the right divided into categories, the utility's tools at the top, and the work area in the center. To start, just choose the color and shape of the piece and, using the top tools, insert them into the work area. You can also rotate them, move them, delete them, paint them, and choose between different camera positions.
The position of the pieces will be represented in coordinates (X, Y, Z) and you can adjust the distance between blocks with the mouse or the environment tools. The most outstanding feature is the categorization of the LEGO blocks, which makes creating models easier (it includes a very useful preview). You'll find both basic and complex tools, turning the environment into one for all users. If you're skilled, you can create models like the following:
LeoCAD is fully compatible with the LDraw standard and can read and edit LDR and MPD files, so you can share your models across the web. LeoCAD is a free program available for Windows, Mac OS X, and Linux.
https://old.neoteo.com/instrucciones-para-modelos-lego/
