Q about convex hull / prim

[Pamela Galli]

I put a mesh shadow prim down on top of my mesh floor.  The shadow prim has a physics shape, and I made it physics type Prim. I made the textured floor under the shadow prim physics type None. Yet my avi floats about 2 inches above the floor.  Any clue what could cause this floating?

[Alisha Matova]

Is the shadow prim a flat mesh plane? If it is, try squishing it flat on its Z axis. I ran into something similar with mesh planes. Instead of being flat, they are 1/4 meter think, or so.

[Pamela Galli]

Yes they are planes, and I made the as thin as they would go, no change. 

[Drongle McMahon]

See if this old thread gives you a clue. Unless things have changed, The avatar always floats a little way above the surface of the physics shapes. This happens even with legacy prims. You can solve it by making the physics shape's surface lower than the to of the visible shape. as described there. Of course you can also always use a linked (invisible) prim as the physics shape too, with the visible floor set to type "None".

Perfectly flat planes are a bit odd because the uploader has to pretend they have thickness, to avoid a divide-by-zero error, I suppose. If you edit them and click "Stretch", you will se a bounding box far away from the plane. I don't know why it's so big. They could have used 0.01m, which you can squeeze it down to. The thick bounding box can also lead to unexpected effexts if you make a plane physical!

ETA: There's also the strange way that they made the default convex hull (the one you get if you don't do the physics shape) smaller than the bounding box. This meand you can actually sink into the visible surface if the object is thick enough.

[Pamela Galli]

Thank you Drongle ;-)

[Chic Aeon]

Drongle taught me how to "fix that" long ago. HOWEVER please note that it does not necessarily stay fixed. When they update the server code things change. I finally gave up and frequently use a prim (which is still iffy). I note that many very well known designers have major issues with the floating thing.

Just be aware that a fix today may not be a fix tomorrow .

 

Currently I am sunk into the ground on a regular prim most days. I use the "hover" code to fix that before taking photos. You can of course make a new shape but that doesn't mean it will work tomorrow - LOL. This is a VERY OLD issue (with prims anyway) and I can remember the problems from six years ago. Best not to worry about it too much.

[Pamela Galli]

I would not worry personally but apparently floating an inch destroys the immersion for some :-)  I decided to do what I usually do, just use a regular prim.