Jump to content

Can't put things down on mesh


Prokofy Neva
 Share

You are about to reply to a thread that has been inactive for 2741 days.

Please take a moment to consider if this thread is worth bumping.

Recommended Posts

I constantly have this experience: I try to put something down on mesh, and the system gives me a message "you can't place anything there."

This happens much of the time, but since sometimes after repeated tries it *doesn't* happen, then I think the problem isn't inherent in mesh but the viewer or my set-up.

Is there such a thing as "poorly-constructed mesh" that makes this happen?

Is this "supposed" to happen so that you can drive on a mesh road and cross it, but not put up a road sign or a rock. You can put out a mesh table, but not expect to put a coffee cup down on it. Unless you rez it elsewhere and then navigate it in "just so".

Or what's the deal?

 

Link to comment
Share on other sites

Please don't take this as a definitive answer. I have done zero testing on this. Every single mesh uploaded needs a physics shape. As you can imagine, this is for physics. Imagine you make a mesh house, without the proper physics shape, you might not be able to walk into that house, or you may be able to walk thru the wall. The physics shape also effects the navmesh. I imagine, that without a proper physics shape, you could have problems like you are having. Also, within the edit options of the mesh, there are options for different kinds of physics shapes. These are None/Prim/Convex Hull. Prim is the physics shape that it was uploaded with. Convex Hull is basically like a plastic bag around the mesh. You could try switching between them, depending on the mesh. I don't make many normal meshes, but I generally have a good physics shape and don't have many problems.

The question is probably better suited for a furniture maker, as they likely deal with this all the time.

Link to comment
Share on other sites

I have absolutely had this problem, and it's just a mesh thing.  The guy above me explains it better than I would be able to.  You set something down and it either appears above or below the floor, or it goes out of bounds and says that you can't set it down.  Unfortunately there's not much one can do about it

Link to comment
Share on other sites

Thanks Medhue. Putting the mesh to convex hull, which I gather the maker should have done from the get-go, fixed that issue on that object on that sim. But I see it didn't fix on another object elsewhere.

I've been told -- and this may only be urban lore -- that you should  put all prims on convex hull now to "save land impact".

I don't see that it does that -- or perhaps it changes only by one prim. I suppose every little bit helps. But the down side is twice I have had builds blow off the sim changing linked things to "convex hull" so I will not do that lightly.

 

Link to comment
Share on other sites

The workround I use is to place an appropriately-shaped, invisible, reguar prim on top of the mesh table.   Then I can rez cups and teapots and so-for on top of it with no difficulty.

It's not a wholly satisfactory solution, I know, and if anyone has a better suggestion I'd love to hear it.   

Link to comment
Share on other sites


Prokofy Neva wrote:

Thanks Medhue. Putting the mesh to convex hull, which I gather the maker should have done from the get-go, fixed that issue on that object on that sim. But I see it didn't fix on another object elsewhere.

I've been told -- and this may only be urban lore -- that you should  put all prims on convex hull now to "save land impact".

I don't see that it does that -- or perhaps it changes only by one prim. I suppose every little bit helps. But the down side is twice I have had builds blow off the sim changing linked things to "convex hull" so I will not do that lightly.

 

Again, I have to say first, I do not upload that many normal meshes, but more avatars and clothing. Generally speaking, convex should be less land impact, because a convex hull is generally less geometry than a "prim" physic shape. That said, the convex hull is generated by LL, not the creator. A smart creator, when making their own physics shape, could do it in a way that is better than the LL generated convex hull. If the mesh has very complex geometry tho, and it needs an exact physics shape, then the "prim" physics shape will almost always be more land impact than convex hull, but the convex hull shape will not follow every contour. Another thing to consider, is that because of LL's crazy land impact system, creators have looked for ways to get lower land impacts, hence leading to some very strange physics shapes, as the physics shape can be the biggest factor in the land impact.

I'm also pretty sure there is a way to see the physics shape in SL. I'm pretty positive, as I've done it before. I'm at a disadvantage on the topic, because I don't generally buy meshes, and I wouldn't see these strange things personally. I'd just makes it myself if I needed something, and I know exactly what my mesh's physics are, so I'm not checking that normally.

Oh, and Prok, if you ever have a question about creating SL stuff, mesh or animation, you can ask me inworld. My inworld time can be sketchy at times, but you'll always eventually get an answer.

Link to comment
Share on other sites


Prokofy Neva wrote:

I constantly have this experience: I try to put something down on mesh, and the system gives me a message "you can't place anything there."

This happens much of the time, but since sometimes after repeated tries it *doesn't* happen, then I think the problem isn't inherent in mesh but the viewer or my set-up.

Is there such a thing as "poorly-constructed mesh" that makes this happen?

Is this "supposed" to happen so that you can drive on a mesh road and cross it, but not put up a road sign or a rock. You can put out a mesh table, but not expect to put a coffee cup down on it. Unless you rez it elsewhere and then navigate it in "just so".

Or what's the deal?

 

Whether you can rez on top of mesh depends on the mesh and also depends on your camera angle when you attempt to rez on top or close to  the mesh.

If you point your camera angle straight down at 90 degrees to the mesh surface or move your camera view further away from the mesh, you can usually rez on top of it - something to do with raycasting I guess.

Alternatively you can place a normal prim on top of the mesh and rez onto that.

The error message that you receive when rezzing on mesh fails depends on your rights on the region you are rezzing on:

If you own all parcels on the region &/or you are an estate manager on the region, you will usually get the "Failed to place object at specified location. Please try again." error message.

If you rez on build enabled land but do not own all parcels on the region you usually  the ""Can't rez object at {x,y,z} because the owner of this land does not allow it. Use the land tool to see land ownership." error.

I attached 2 repro dae's on  https://jira.secondlife.com/browse/BUG-2019 which show this problem.

You will find that you can always rez ontop of generic cube1.dae but rezzing on top of Mesh Quad.dae will usually fail  unless you move camera view further away or point your camera down directly onto the mesh.

See last comment on that JIRA issue for more detailed results.

Link to comment
Share on other sites

  • 2 weeks later...

This problem occurs with meshes uploaded with hull physics made from incomplete hulls. It's yet another "undocumented feature" in SL's mesh handling but it's easy to work around and every decent mesh maker know how by now: you either use triangle physics or you assemble a hull physics model from completed hulls with no gaps in them.

There are lots of mesh made by builders still learning the art though and also lots of older mesh made before anybody figured out what was going on so we'll have to live with the problem for a long time.

Link to comment
Share on other sites

You are about to reply to a thread that has been inactive for 2741 days.

Please take a moment to consider if this thread is worth bumping.

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...