Choose simulation configuration
1. Choose configuration saved in browser or on disk check
info Configures the simulation to match the setup of a UIAA norm fall (see UIAA safety standards). Note that the UIAA standard setup cannot be exactly reproduced because a simplified model is used in this simulation. Also note that the simulation currently does not yet fully support configuring a viscoelastic rope model (only the linear spring model can be fully configured). This means that the forces measured by rope manufacturers during a UIAA norm fall will not match the simulated forces exactly, even if you input the exact rope specifications.
info Below, you can load saved simulation results. Saving and loading only the simulation configurations is currently not yet supported.
Load from file:
info Load simulation result from a JSON file that you saved on your computer’s disk.
Automatically saved simulation results
Simulation results saved by the user
1. Basic setup check
info This simulation runs in 3D space. The belayer (or fixed anchor) is always assumed to be located at the point with x-, y-, and z-coordinate equal to 0 meters. Everything else is placed relative to the belayer or fixed anchor. The simulation uses a coordinate system where the y-coordinate corresponds to height, the x-axis runs orthogonal to the base of the climbing wall, with greater x-coordinate values corresponding to a greater distance from the climbing wall, and the z-axis runs parallel to the base of the climbing wall, that is, it can be used for placing objects to the side of the belayer.
degrees
info Supply a number in degrees, between -30 and 70. Positive values correspond to the angle at which the wall is overhanging. 0° corresponds to vertical, 70° corresponds to an extremely overhanging wall, which is almost a horizontal roof. Negative values correspond to inclined, slabby terrain.
info Whether the ground is present at the height specified below. If unchecked (currently not yet supported), no ground will be present in the simulation, which would correspond to multipitch settings, for example.
meters
info Supply a number in meters, between -8 and 0. This number corresponds to how many meters the ground (if present at all) is placed below the belayer (or fixed anchor). In a multipitch setting, you can use this to indicate that a big ledge is located not far beneath the anchor, for example. If the ground is placed below a moving belayer, who is not attached to an anchor, then the belayer will fall downwards at the start of the simulation.
meters
info Supply a number in meters, between -2 and 50. This corresponds to the number of meters the climber is located above the belayer (or fixed anchor). Only values above the ground level are allowed.
meters
info Supply a number in meters, between -25 and 25. This corresponds to the number of meters the climber is placed to the left (negative value) or to the right (positive value) of the belayer (or fixed anchor).
kilograms
info Supply a weight in kilograms, between 1 and 150. The climber is currently represented only as a point of zero volume, but with a positive mass.
meters
info Supply a number in meters, between -2 and 50. This corresponds to the number of meters the last clipped quick draw (or other protection point) is located above the belayer (or fixed anchor). Only values above the ground level are allowed. This value is ignored if you specify 0 clipped draws in the next field.
info Supply a number between 0 and 15. This corresponds to the number of clipped quick draws (or other protection points) between the belayer (or fixed anchor) and the climber. 0 draws corresponds to a fall directly into the anchor (interesting for multipitch settings). The exact positions of these draws can be adapted in the next step.
info Whether the belayer’s end of the rope is attached to a fixed point. If this box is checked, the end of the rope opposite to the climber’s end is assumed to be fixedly attached to a protection point in the wall with a knot. Otherwise, a moving belayer is assumed to be attached to the end of the rope. Rope slippage through a belay device is currently not supported.
info Whether the belayer is attached to an anchor via a static or dynamic sling (currently not yet supported), which is usually the case in multipitch settings. If you have selected fixed anchor above, then this setting has no effect.
kilograms
info Supply a weight in kilograms, between 1 and 150. The belayer is currently represented only as a point of zero volume, but with a positive mass. If you have selected fixed anchor above, then this setting has no effect.
meters
info Supply a number in meters, between 0 and 1. This number corresponds to how much slack will be added to the rope. 0 meters of slack means that the rope is tight at the beginning of the simulation. Please note: slack is currently not well integrated into the simulation. If you supply a large amount of slack, the rope will still start as a straight line between belayer, quick draws and climber at the beginning of the simulation, but in a compressed state. The rope will then explode outwards at the beginning of the simulation to reach its actual length. This causes large forces to appear at the beginning of the simulation, which do not match what would happen in reality. It is planned to improve the slack handling in the simulation at some point in the future.
1. Quick draw setup check
info Supply a (unitless) number between 0 and 10. This specifies the coefficient of friction between carabiners and rope. The higher the coefficient of friction, the more friction occurs between rope and carabiners. Check Wikipedia on the capstan equation to see how the coefficient of friction enters into force calculations. In this model of the real world, the carabiner diameter does not influence the amount of friction.
info Whether to add slings to every quick draw for a more realistic animation. If unchecked, each quick draw is simply a fixed point at the specified location and does not move (as if the rope was passing directly through the bolts). If checked, the carabiners are attached to a fixed bolt on the wall via a static sling with a length of 20 cm (the quick draw to wall distance setting is ignored in this case). The overall effect on the simulation is relatively small. However, note that when using slings, carabiners will be hanging 20 cm lower than when using fixed quick draw positions, resulting in an increased fall height.
info Below, you can change the height of every quick draw (or other protection point). The draws are numbered from the belayer’s (or fixed anchor’s) side, starting with 1, in ascending order up to the climber’s side. Heights may be between -2 and 50 meters, and must be above the ground level. Next to the height, you can also specify sideways shifts between -25 and 25 meters. These correspond to the number of meters the corresponding draw is placed to the left (negative value) or to the right (positive value) of the belayer (or fixed anchor).
1. Distances to the wall check
meters
info Supply a number between 0.01 and 10. This specifies the distance of the belayer to the wall, measured parallel to the ground (that is, along a horizontal line).
meters
info Supply a number between 0.01 and 10. This specifies the distance of the climber to the wall, measured parallel to the ground (that is, along a horizontal line).
info Below, you can change the distance of every quick draw (or other protection point) to the wall. The distances may be between 0.01 and 10 and are measured parallel to the ground (that is, along a horizontal line).
1. Rope properties check
kilonewton
info The impact force in kilonewton, measured during a UIAA norm fall of an 80 kg mass with a fall factor of around 1.8 and with a rope of approximate length 2.6 meters. The force is measured between the rope and the falling mass. Rope manufacturers must provide this information for UIAA certification (UIAA norm 101, EN 892, see UIAA safety standards).
%
info The relative static elongation of a rope of length 1 meter under a load of 80 kg. Rope manufacturers must provide this value.
%
info The relative dynamic elongation of a rope with a length of about 2.6 meters under a UIAA norm fall of an 80 kg mass with a fall factor of around 1.8. Rope manufacturers must provide this value.
info You can either enter the elasticity constant of the rope directly (see next input field), or you can enter data provided by a rope manufacturer (impact force, static elongation, dynamic elongation). If entering rope manufacturer data, the elasticity constant will be estimated automatically.
×10-3 per Newton
info The elasticity constant measures the relative amount by which the rope stretches if a stretching force of 1 Newton is applied. That is, if a rope has a rest length of 5 meters, the elasticity constant is 0.1×10-3 per Newton, and a force of 2 Newton is applied, then the rope will stretch by 5 × 0.1×10-3 × 2 = 10-3 meters.
kilograms per meter
info The weight of 1 meter of rope. This value will be multiplied with the rope length to obtain the rope weight.
info How to model the climbing rope. If modelled as a linear spring, the contracting spring force is proportional to the spring's (i.e., rope's) extension. The standard linear solid (SLS) model (Wikipedia) adds viscous damping. In the current version, the SLS model parameters are set to reasonable values, given the elasticity constant supplied above. In future versions, it is planned to add more fine-grained control over the SLS model parameters.
info How much to damp rope bends. The value has no direct physical meaning, but the higher the value, the stiffer the rope is (the less oscillations orthogonal to the rope appear and the less the rope bends at rope segment joins).
info How much to damp rope stretching. The value has no direct physical meaning, but the higher the value, the less “springy” the rope is (rope length changes due to stretching are damped to a higher extent). Note that the rope is currently modelled as a linear spring. The effect of the stretch damping parameter is quite limited, in contrast to the viscous damping in the standard linear solid model which you can choose above.
1. Physics engine settings check
info Supply a number between 2 and 500. This corresponds to the number of rope segments into which the climbing rope is subdivided. The more segments, the more realistic the rope behavior will look in the final simulation. However, a higher number also requires more processing power during the simulation, that is, the simulation will take longer.
milliseconds
info The step size of a single simulation step. During such a step, constant forces are assumed, and the forces are recalculated before every simulation step. This value must be small enough in order to avoid instabilities.
1. Start the simulation check
FPS
info The frame rate (number of frames per second) at which the simulation results will be captured. This is not related to the step size of the physics simulation engine; instead, this just indicates at which rate simulation results will be captured and stored for the resulting animation and graphs. To get a fluid animation, a frame rate of at least 30 FPS is recommended. If you want to view the result in slow motion, higher frame rates are necessary. This setting also influences how many data points are available for the graphs displaying forces, energy, heights and speed of the different objects. The higher the rate, the higher the resolution of these graphs.
seconds
info Number of seconds for which the climbing fall should be simulated.
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Climbing fall simulation

© Fabian Michel
Published under the MIT License