The vegetation tool is almost finished. Here I have s short video that shows the current version (click on the image):
Several models can be grouped together and will be then placed randomly on the clicked position within a defined radius. You can also set random rotation, random scaling and many more parameters. Removing vegetation is done the same way as creating, just select the models in the list on the left you want to remove, then only the selected models will be removed if you move the brush through the level.
