Vary copies

Scatter twenty rocks and they are twenty of the same rock. The eye picks that up immediately, and no amount of adding more fixes it. What fixes it is giving each copy its own size, its own turn, or its own colour, from one extra node.

When you need this your copies are all identical and the result looks stamped out rather than placed.

One node, a different answer each time

Wire a Random Value into the Scale of your instancing and every copy gets its own size. You did not write twenty numbers; you described a range and each point took a value from it.

That is worth pausing on, because it is the idea the whole app is built around. A value can be a single number, or it can be a value that answers differently depending on which thing is asking. Feed one into something that makes many copies and each copy gets its own answer.

Once you have seen it, the name is useful: values that behave this way are called fields.

Variation does not have to be random

Random is the obvious source and the least interesting one. Anything that knows about a copy can drive it.

Distance from a point makes rocks large in the middle and small at the edges, which reads as a mound rather than a scatter. Height makes snow appear only near the top. Noise gives you patches instead of static, so clumps of tall grass sit together the way real ones do.

Reach for random when you want to break up repetition, and for position when you want the variation to mean something.

Keeping it under control

Two knobs beat one slider. A smallest and a biggest read plainly, and they stop you having to explain what 0.4 means.

Give the randomness its own seed knob. It rerolls the arrangement without changing anything else, which is the fastest way to find a version you like.

What it can and cannot reach

Scale, rotation and colour vary per copy. That covers most of what makes a scatter look natural.

What varies per copy is not the same as what varies per face inside one shape. If you want the individual rock to change shape rather than change size, that is a different tool, and it belongs to selections.