View source for Population Instance Editing

===Introduction===
The [[Populator_v4|Populator v4]] (new in Terragen 3) node allows you to edit individual instances in a population. You can modify the transform for an instance, in other words change its position, rotation or scale. You can also delete instances. All of these changes can be reversed to put an instance back to its original state if needed.

===Start Editing a Population===
There are several ways to start editing a population:
* Click the "Edit Population" button at the top of the 3D Preview. This will pop up a menu allowing you to choose a population to edit.
* The '''Editing''' tab of the [[Populator_v4|Populator v4]] node has a '''Start Editing''' button. Click this button to start editing the population in the last 3D Preview you were using.
* You can context click on the population's handle in the 3D Preview, then choose the "Start Editing Population Instances" item. 

Starting to edit a population will put the 3D Preview into instance editing mode. When you are editing a population you're not able to interact with other objects or shaders in the 3D Preview, only the instances of that population. You need to finish editing the population (see below) to return the preview to normal.

When you mouse over a population instance its bounding box will highlight in orange. Click to select that instance. You can shift-click to add multiple instances to the selection. Selected instances are drawn with yellow bounding boxes.

===Deleting Instances===
To delete a population instance select it and then press the Delete key. You can delete more than one instance at a time.

You can display deleted instances by going to the '''Editing''' tab in the Populator v4 parameter view and checking '''Show deleted instances'''. Deleted instances are drawn with a red bounding box.

Deleted instances can be restored to the population. You can restore all deleted instances using the '''Restore Deleted''' button in the Populator v4 Editing tab. You can also restore specific instances. To do this you need to make sure you're displaying deleted instances, as described above. This allows you to select deleted instances. Press shift-delete to restore the selected instances.

===Modifying Instance Transformations===
The position/translation, rotation and scale of population instances can be modified. Simply select an instance in the preview and the usual transform handles become available, including the "Drop to Terrain" button. You can only modify one instance at a time.

If you want to see all modified instances you can go to the Editing tab of the Populator v4 node and check the '''Highlight modified instances''' checkbox. This will draw all the modified instances with green bounding boxes.

Modified instances can be reset to their original location. You can reset all modified instances using the '''Reset Modified''' button in the Populator v4 Editing tab. You can also reset specific instances. Press shift-R to reset the selected instances.

===Finish Editing a Population===
There are several ways to finish editing a population:

* Go to the "Edit Population" button at the top of the 3D Preview. Click it to pop up the menu, where you will see an item that allows you to stop editing the population.
* Context click anywhere in a 3D Preview that's in instance editing mode you will see a "Finish Editing Population Instances" item in the Context menu. Select that item to finish editing.
* There's a '''Stop Editing''' button in the '''Editing tab''' of the Populator v4 node. Click that to finish editing the population.

When you finish editing a population the 3D Preview will return to its normal mode.

===Hints and Tips===
Moving or translating an instance happens relative to the original instance position. This means that if you move the population as a whole any edited instances will move along with it. At the moment edited instances do not retain their relative positions if you rotate the population.

Modifications and deletions will persist across repopulation. While we intend to ensure this as much as possible we will be making changes so that changes to certain population settings invalidate modifications and deletions.