Using sculpted steps/staircase

[SinfulPrince]

I know this is probably a very basic question for a lot of people but not for me lol . I recently purchased a set of sculpted stairs no matter how I seem to place them within  a house my av is unable to walk up them, Around them, but not up them. Is there some trick to placing them. I noticed that  even in a purchased house where the sculpted stairs worked perfectly fine when rezzeed from the box, if taken into inventory and then attempting to replace them, again they seemed to be unable to be walked up.

[Luca Coeur]

Maybe your  working stairs consist of two prims: a visible sculpted stair which is set phantom and a non phantom but invisible ramp to walk on. Together both prims create the illusion of walking on the stairs. If you rezz out only the sculpty stairs then you walk through the (phantom) prim or - if set non phantom - you may run against a wall.

[Carbon Philter]

Sculpties have a bounding box which doesn't follow the visble modelled shape of the object but is a cube matching the max dimensions of the the modelled shape. So if the stairs were made with the world's xyz axes as the basis you'll get the problem you are experiencing.

You either need to make the stair phantom and put an invisible non-phantom prim along the pitch of the stair which you can walk on. This means you then need to leave the sculptie unlinked or use a scripting trick to allow you to link a phantom child to the rest of the linkset.

If you're making single flight sculptie stairs yourself, create the sculpt mesh in whatever programme you use - I use Blender - and then rotate it so that the nosing of the stair is on one of the major axes before you bake the sculpt UV mesh. That way the nosings of the stair will become the face of the sculptie bounding box and you can keep it non-phantom and link it to the rest of the house and still walk up it.

[Indio Quinnell]

If you look through the "Building Components" area of the Marketplace, you'll find a number of sculpted staircases that are made so that they can be walked on without needing a phantom prim.  The important thing to look for is that it explicitly states, in the description, "no phantom prim needed", "walkable surface", or "perfect bounding box."  

(Don't go solely by the prim count, because some of them will claim "1 prim" and then have a disclaimer of "does not include invisible plank you'll need to walk on" buried in the description somewhere.) 

[SinfulPrince]

Thanks everybody :matte-motes-grin:

[Drongle McMahon]

The physics shape of a sculpty is actually the convex hull of a torus, that is a torus with the hole closed with a flat disc at top and bottom. This is demonstrated in the first picture. The left two panels show a sculpty sphere with a narrow nearly-transparent box crossing at its center. Small physical spheres have been poured into the box with the sculpty in two different orientations. On the left, we are looking along the X axis (grid set to local).  The physics shape of the sculpty in the YZ plane is a circle. In the middle panel, the X axis is vertical. You can see the flat top and bottom and the extra space from which the the physical balls are excluded by the physics shape. On the right is the convex hull of a 1x1x1 torus (with equal major and minor radii). Note that the vertical section of this is the same as the outline of the physics shape revealed in the panel to its left.

This physical shape does work as you describe for steps with no phantom slope. It can be in three different orientations depending on which direction the X axis, with the falttened top and bottom, points on the stairs.  I'm not sure which is the best. Probably it's the one shown at the top of the three here (physics shapes grey), with the X axis along the long dimension. That has the flat ends at the ends of the stairs, giving the least step area that you could fall through near the ends.  On the other hand, the second one, with the X axis pointing from bottom to top of the stairs, gives a flatter surface in the middle. In the third choice, with the flat surfaces running along the sides, we get the maximum region where the physics shape is the full width of the stairs.

The phsyics shape always reaches to the sides of the 255 unit cube maximum sculpty range. If you use less than the full range in any dimension, that is any of the RGB channels of the sculpt map, the shape will stretch and protrude beyond the visible sculpty in that dimension. In this way, the physics shape in the first option can be stretched (2x) relative to the width of the stairs so that there are no parts where you could fall through it. This might be needed for very wide staircases. However, it would only be useful when collisions with the protruding physics shape from each side were acceptable. This is shown in the fourth set of stairs.

[Josh Susanto]

I sell one set of sculpted stairs which I never intended to be used structurally.

If that's the set of stairs we're talking about, I'm pretty sure that I can adjust it so that it works better physically, but this will mean a 45 degree shift of axis that will make them more difficult to adjust to properly fit the space in which you want to use them.

In fact, as always, if you will post the data in the current item, I'll be happy to try to provide some improvement for free in-world and post the data here for anyone who wants to grab and load at their own cost.