[jrm1]

I'm still working mainly in Sketchup, as I find C4D still a bit complex and therefore slow for my needs, but I know that soon I'll be able to make the jump to C4D and never look back.

One hurdle I have is applying grass to a selection of ploys. In my present model, I have selected a bunch of polys that I want to turn into grass. I make a Set Selection command. Now I want to turn that into grass using the Maxwell Grass extension. I must be doing something wrong. What I am doing is this:
I highlight the selection tag and click on Select Polygons in the Attributes Manager. I then make a Grass tag. This appears at the front (left) of the row in the Object manager. I drag it to the right and then go back to the selection tag, restore polygons or select and hide others just to be sure. Then I drag the grass tag object into the viewport and drop it onto the selected polygons. (was that my first mistake?!) I then render the scene and the grass has been populated over the entire object instead of just the selection of polys.

I also tried selecting the Selection tag of the intended grass area, and dropping the Grass tag into the Name box of the Selection tag. Probably also bonkers.

[JDHill]

The problem will be that it's not currently supported to apply grass to only some triangles of a given mesh. I'll see about adding this in the future (I see the extension does have a TRIANGLES_WITH_BLADES parameter, which I've not yet used), but for now, you'd need to physically split the geometry and apply grass to only the desired pieces.

[jrm1]

So should I take the polys out of the object and make them into a new and separate object? I prefer that way anyway. Seems easier to identify parts of geometry, easier than sifting through selection tags.

[JDHill]

Yes, that's what I meant. And probably best not to hold your breath on selection tags for grass anyway, since it gets pretty complicated, given how the plugin allows applying grass to whole trees of of objects with a single grass tag.

[jrm1]

OK thanks. Have done that and it's made my life easier.