added interpolation to helpcenter (#26)

* added interpolation

* added line about arrow in project tree

* minimal wording fix

Author: wiktor-flex

docs/01.introduction/05.project-tree.md

@@ -21,6 +21,7 @@
 | <img src="./Figures/volume_mesh.svg" width="32" height="32" alt="volume mesh"/> | Volume Mesh | Represents the 3D computational mesh used for simulation |
 | <img src="./Figures/case.svg" width="32" height="32" alt="case"/> | Case | Represents a simulation case with defined parameters |
 | <img src="./Figures/fork.svg" width="32" height="32" alt="fork"/> | Fork | Indicates a continuation / branched variant of an existing parent |
+| <img src="./Figures/interpolate.svg" width="32" height="32" alt="interpolate"/> | Interpolate | Highlights a case that has been interpolated onto a different mesh |
 | <img src="./Figures/draft.svg" width="32" height="32" alt="draft"/> | Draft | Represents a simulation setup that hasn't been run yet |
 
 ---
@@ -115,6 +116,13 @@ The project tree supports multiple branches at each level:
 - Simulation continues from the last state of the parent case
 - Multiple forks can branch from the same parent case
 
+### **Interpolation**
+
+- Interpolation transfers solution from a case onto a new mesh
+- New mesh can exist either within the same project, or in a different one
+- Useful when running a refined mesh or slightly altered geometry
+- Arrow on the volume mesh asset icon in project tree indicates that the volume mesh exists in a different project
+
 ### **Component Actions**
 
 When clicking on a component in the project tree, a menu of available actions appears. Below are the available actions:
@@ -127,7 +135,7 @@ When clicking on a component in the project tree, a menu of available actions ap
 |------------|-----------------|
 | Open in workbench | Opens the component workbench |
 | New run | Creates a new simulation run draft using settings from this component |
-| Interpolation | Transfers solution data between different mesh resolutions |
+| Interpolation | Transfers solution data between different meshes |
 | Rename | Changes the display name of the component |
 | Details | Shows components details such as ID, name, cost, parent asset ID, etc. |
 | Expand all sub-items | Shows all sub-components derived from this component |