Dear all,

I was looking into the conveyor demo and specifically why it didn't work. As it turns out it is due to a patch not having been merged until dart6.13.

Anyway, before I realized that I had been looking extensively at the source code, and there's a certain mechanism I'd like to understand better:

Given a dart version < 6.13, DART_HAS_CONTACT_SURFACE is not set, so this featurelist does not contain SetContactPropertiesCallbackFeature, and consequentially neither the DartsimFeatures.

This results in this EntityCast returning nullptr.

Can anyone clarify this a bit?

It seems that:

• EntityCast calls RequestFeatures::From,
• Which is implemented here.

I didn't dig into that further, as it is rather hard to read (for me at least :-) and it answers the how is the cast done question, but not where is the relation between the world entity and the DartsimFeatures defined?

I think this might be it, but I don't see how the worldPtrPhys is linked to the DartsimFeatures.

Can anyone clarify this?

Thanks

  public: using WorldEntityMap = EntityFeatureMap3d<
          physics::World,
          MinimumFeatureList,
          CollisionFeatureList,
          ContactFeatureList,
          SetContactPropertiesCallbackFeatureList,
          NestedModelFeatureList,
          CollisionDetectorFeatureList,
          SolverFeatureList>;