Simulate

Use Blender physics to simulate a cable with collisions while keeping the points number low.

Please note that since Blender doesn’t support physics for curves, the function could give weird results — especially in difficult scenarios with a lot of intersections and colliders. In most cases Simulate should be considered as a base for further manual adjustments. Please check the Best Practices section below for some hints.

  • Only one curve object can be simulated at a time; however the curve object may contain several splines (aka sub-curves).

  • If Mesh objects are selected before running the function they will be considered as colliders for curves.

  • By default the first and the last points of each spline are locked in place. For locking specific points, select them in Edit Mode before running the function (and run the function while in Edit Mode).

Simulate Options:

  • Run Curve Refit in the End: new in 1.6, this option replaces the old Refit function. With this option selected, Refit Mesh or Cable will run after the simulation;

  • Expand Length: will make the cable curve longer;

  • Curve Points Multiplier: with the default value set to 1, the result of simulation will have the same amount of points as the original curve had. However, in situations when simulating with a collider it’s better to have more points. Change this option to add more points effectively increasing the resolution;

  • Debug Mode: when enabled the result of the Simulate will be a baked simulated mesh object — the simulation can be played using the Blender Play Animation button. This could be helpful to understand what’s happening in case of weird / unexpected results. Also could be useful to look for a specific frame to stop the animation. Use Undo to restore the pre-baked curve back;

  • Use Custom End Frame: by default the 400th frame of the simulation is used. In some cases it could make sense to use a different frame: if the result of Debug showed some better results;

Example of using Simulate with Refit function new to 1.6:

Best Practices for Simulations

  • consider the location and number of curve points before simulation: sometimes fewer points give better results, sometimes adding one or two points could help the curve to achieve a better simulated pose;

  • it’s possible to lock specific points in place: select them before simulating and run Simulate in Edit Mode;

  • in some cases it makes sense to cut a complex curve into smaller parts using the Cut Bezier Curve helper; use Merge End Points to make the curve single again;

  • Cut Bezier Curve helper is also useful to separate the result of a simulation of a Create a Mass from Selected Faces before editing — separated curves are easier to edit;

  • for laying the curve down on a large flat surface consider using Drop the Cable helper instead;

  • other curve objects can’t be colliders: if collision against a curve is needed, duplicate a curve, convert the duplicate to a mesh and use the duplicate as a collider. Remove it after the simulation;

An example of tweaking a curve for achieving a particular simulation result. While the first simulation gave an adequate result, I wanted to have a little hanging part on the left. I first rerun the simulation in Debug mode and noticed that frame 70 gives a result I like. So I rerun the simulation with this custom end frame. However, the result was too wobbly. In the end I decided to lock a specific point in space: selecting a collider object first, then going to Edit Mode and selecting the points to lock. This finally gave a result I was satisfied with.