@Khalid_Noh - Regarding floor slab and column export, are you referring to exporting from Revit to SketchUp or SketchUp to Revit?
For SketchUp to Revit, we support Converting to Revit native floor slabs, but we don’t support converting to native Revit columns. To see a complete list of SketchUp to Revit element support, see this post: SketchUp to Revit - Supported Categories and Mapping
For Revit to SketchUp, all elements visible in Revit should export to SketchUp. If this is not the case, we would like to see the issue so that we can update Helix and make sure that it’s compatible with the geometry that you are testing. Please let me know if you can share your model to demo this, if this is the case.
Regarding syncing from SketchUp to Revit but not vice versa: at the moment bringing the geometry from Revit to SketchUp is a one time thing, meaning that it would disregard if you’ve already brought the geometry from Revit to SketchUp. SketchUp receives a new group of all the Revit content (with subgroups) whenever you import from Revit. We have a feature in the roadmap that will allow the Revit to SketchUp geometry to only update if necessary instead of bringing it in every time. To see what is on our roadmap, see this post: Helix SketchUp ⇌ Revit | Feature Roadmap