OBD 9 Compound Slab Worries

Just started playing around with the new Compound Slab tool. This is shaping up to be quite a promising tool. Billed as an update of the old Triforma Forms-based Slab, it seems to work better with Constraints which is great. Rumour is that the oldish Triforma Morph Form based Roofs and old stalwart Walls are next in line. It would be good to be able to form persistent L-T and mitred joins between Slabs and Walls and Roofs in future, something Triforma's estranged cousin BricsCAD BIM can already do.

The old Triforma slab was very flexible but was not much of team player, requiring a lot of manual tweaking. The coder did not really have to understand how the real life object that the tool was mimicking needed to behave. The new Compound Slab seems to have taken a more tailored approach and tries to automate a particular use case. I think that this is a good starting point, but there needs to an exit strategy for tools that are developed this way.

Covering even 90% of the use cases will still be a problem (the CS tool only covers maybe 20%). There should be a way to 'drop' the CS to its components without losing too much of its relationship, F&P, materials, DGS etc assignments. CS seems to be making the same mistake the Compound Walls, which added a 'guide line' object to store the group info... belatedly and half heartedly.

For example, the edge setback is a nice touch. But, in reality, you will find that some edges will need them, some won't and some will require different thicknesses. What happens when you punch a hole in the CS for slab penetrations, columns etc. Fire stopping set backs will be different to perimeter 'randstreifen' movement gaps. Not all bounding elements are vertical.The new parametrics are great... for the first pass.

Typical for screeds to be sloped to falls in wet WC, shower and kitchen type areas. R*vit had to add all kinds of clumsy tools to its slabs to handle this. CS seems to ignore this altogether? Over the course of the design, you need to let the modify the components without losing the classification, F&P etc info... while preserving certain parametric controls like thicknesses which willl be good to be able to bulk edit.

Geometric flexibility

As mentioned, the old Triforma Form tools are quite flexible. A 'slab' could be vertical or sloping. But, the Triforma APIs seem to fallen into maintenance mode after the Bricsys split? And never really interacted very well with Mstn regular solids, constraints tools. Rewriting using Mstn APIs is long overdue. But this should be done with 'extreme modeling' XM 2.0 in mind. Mstn was the tool of choice over a lot of other apps including R*vit, ArchiCAD etc because it could model just about anything... albeit not parametrically.

So, it is worrying to see how badly the CS tool deals with sloped slabs.

The Compound Slab Direction / Angle parameter seems to be a structural parameter to do with the way the slab spans. This is a bit silly for screeds and floor covering build ups. If this is included because one of the slabs could be structural then this needs to be made clear in the Modify Properties panel which has a single parameter for all the component slabs. This parameter should be about what direction the component slabs are extruded: vertical or an angle from the vertical. The old Triforma slabs do a much better job here. Hopefully to be corrected in U10.... I think this will definitely be required for roof modeling.

Flooring: need to look beyond the residential market. It would be good to be able to extrude meshes and facetted shapes. This will be much more the norm that flat / level floor buildups in small resi or BoH rooms. Sure, I can see starting with something simple is the 'Agile' way, but the main event awaits.

Mstn is well placed to deal with hard landscaping / paving where the paving plane is inevitably facetted to allow for falls / drainage, drop kerbs etc. Mstn's slope thematic Display Style is still pretty unique; its CAD orientation is much better suited to coordinating with site surveys and 2d info.

Compound Slab - sloped.dgn