I'm just starting to learn to make objects and am finding it rather confusing - some of my objects come out successfully first try and work fine, some need a second or third attempt but get there in the end, but others do a strange disappearing act when used, and I can not figure out what to do. I converted this lovely comfy 'bed' from TS2 - looks fine in-game, and the game even generated various recolours for it, which I was not expecting, so I was really pleased with it. However, when a sim goes to sleep in it, it disappears.

It doesn't even re-appear when he's finished, which other disappearing objects I've ended up with at least do - when this one's gone, it's gone. Except that it leaves its shadow behind, and going back into Buy Mode, the game apparently thinks the bed is still there as it doesn't let you place anything else on that spot, but it won't let you delete the bed either.

I saw another thread re objects disappearing upon use in this forum, and someone suggested the OP hadn't assigned joints to their object. The OP said he would go and check the joints, but hasn't returned to the post since then. In my case, joints do seem to be assigned (about 20 of them), retained from the bed I cloned from before importing the .obj file of the vampire coffin. Here's a screenie of my Milkshape screen showing (some of) the joints.

Can anyone advise? Thanks!!

It is definitely the joints. The problem is finding the correct one, and just because nothing is assigned doesn't mean the joint is gone. Normally you would reassign the frame to the joint the original frame was assigned to and leave the bedding joints assigned as is - which are different joints than the frame. Since you have removed the bedding, there is nothing assigned to that joint. I am really not sure what should be assigned to what joint here. :/ You could try assigning all of the mesh to all of the joints that were previously assigned to any part of the bed frame or bedding.

Thank you!! It works now! It *was* just a joint assignment that was needed, and it seems the bed is just assigned to one joint, 0x6939C131. Once I assigned the joint, it worked fine. Vampires can now have their own special place to sleep:

What does 0x6939C131 mean? Is there a list of what each joint number means? I'm used to making CAS Parts, and their joints are called such things as 'Spine1', 'Pelvis', 'Right Forearm', etc, rather than strings of numbers - a lot easier to figure out, ha ha!

Thanks again!

Awesome! Glad it was just one joint to assign.

I think that joint name is an FNV32 hash of the bone/joint name, which you can't normally see but I think it is coded into the object. Probably could be seen in a program like Granny Viewer, if you wanted to see an exact sample of the slot name/FNV32 hash there is a thread object slot height or object height here in modding. So in a different object the joint could be a different number, so next time keep in mind to make note of which joint name it was.

Ah, that's interesting, so joints involve a bit of guesswork with objects unlike with CAS parts. Thanks again for your help!