Shade , Drop and Prune

Shade, Drop and Prune

Witness branches compete for light – drop them when too little is available. Evolve your trees into airy branching structures.

If a tree held on to every branch it grew, it would soon become a dense green ball that would collapse under its own weight. To escape this horrible fate, it drops all but the most successful branches. Dropping branches keeps the tree airy and allows light into the crown. This is the exact opposite to space colonization and yields far more natural results at the cost of more calculation time – but staying true to nature.

The Grove has 3 ways of removing unwanted branches:

  1. The tree itself drops shaded and low power branches all the time.
  2. Automatic pruning of the lower base will save you a lot of time.
  3. Manual pruning allows you to cut individual branches by hand, or to trim many branches at once by drawing cutting lines.

Shade

Trees grow up to the sky, competing with neighbors that take away light. But the biggest competition is the very tree itself, where new leaves above shade the old underneath.


Light is vital for trees. Most branches are dropped because of low light. To calculate shade, and to be able to grow sensitive trees, the Grove uses raytracing to calculate real shade. It works on the entire tree and can even include an environment. The results are smooth values from light to dark, calculated for each branch.

Ray Tracing

Let’s take a look at how shade is calculated. The first thing you should know is that branch tips are the eyes of the tree, and that they are looking for blue sky light. This is the light that makes trees grow into balanced shapes.

The interactive Shade Preview offers you a view behind the scenes, you can find the circle icon in the Shade panel. It shows you where The Grove distributes shadow casting areas and just how big they are. You will see that it places polygons at branch ends. When a branch gets increasingly vertical, the area’s center is shifted toward the branch end, matching the placement of real leaves around the branch. The size of each area is controlled by Leaf Area.


The default values work well in most situations and you should rarely have to tweak them.

Shade Preview also shows the ray tracing samples. This uses a phyllotaxic distribution of samples – the same natural distribution seen in sunflower seeds and pinecones. It’s only fitting to use this optimal distribution to sample the light environment. Increase Shade Samples for accuracy and smoothness, while fewer samples will introduce randomness.

Environment Shade

You can see the effects of Turn > To Light on single trees or multiple trees growing together. But it is best visible in trees avoiding buildings or natural obstacles. The Shade + Block environment type includes the environment’s polygons in shade calculation.

Drop

Branches evolve and grow to the light. But when it gets crowded and they end up in shade, branches will wither and drop to the ground.

Drop Shaded

Alright, we’ve calculated the shade of every branch end. Now it’s time to drop the low performers. By far most branches are dropped because of low light. A higher Drop > Shaded will drop more branches, as simple as that. Drop Shaded only drops young branches (without child branches). Older branches can be dropped with Drop > Obsolete.

Drop Obsolete

This doesn’t only happen when you pick up a chainsaw and prune the tree too heavily. It happens all the time in nature, when the crown grows bigger and shades the lower branches. These lower branches will slow down and even lose many of their smaller twigs due to a lack of light, to the point where the branch is thicker than it needs to be – too thick for its dwindling leaves to keep it healthy.

When there’s just too much excess wood, the few remaining leaves can’t keep the flow of water going when conditions become dry. This is when the branch will dry out and die.

Prune

Nurture your tree like mother nature, or dive in with the pruning tool! Remove the branches that block the view, create space and air, and neat contours.

manualprune

Manual Prune

Prune realistically cuts off branches and leaves thick and dead branch ends. A handy tool for cutting off larger branches.

Interactive pruning is fun to play with, extremely addictive, and gives rise to many more tree shapes, and even extremes like pollarded plane trees and pollarded willows.

To prune your tree, simply click Prune and draw cutting lines in the 3D view.

Regenerate

Trees respond like crazy to pruning. The excess wood volume contains so much energy that it will create regenerative branches from old wood.

Paired with the Prune tool, trees will soon recover from the tyranny you impose on them. Gaping holes will soon fill up, all thanks to the shade calculation!

Regenerative branches, or watershoots as they are often called, usually develop after damage caused by lightning, storms and falling neighbor trees. Although watershoots are natural, they are a common but unwanted sight on the trunks of city trees. The extreme pruning imposed on city dwelling trees is often the cause of many watershoots. Use Auto Prune > Low for regular maintenance of your trunks.

Auto Prune

Drop Shaded and especially Drop Obsolete will clear the base of your tree when the tree grows older. But not enough. On the forest floor, animals eat the tasty green branches of your growing tree. They can only reach a certain height. In the city, trees are pruned to a certain height so they don’t hinder traffic. Auto Prune > Low is a handy automatic pruning tool that performs its work each year. Low lets you define a height up to where the base should be cleared. It gradually kicks in, when the tree grows higher than the set height. So a smaller tree will not be pruned. Only when the tree grows to twice the height, it’s base will be cleared to the full Low height. Keep Thick will keep thicker branches.