how to handle physics on this, advice please

[Bitsy Buccaneer]

Hi everyone. This is the first thing I've made from mesh which an avatar could go in and I'm not sure what the best way to handle the physics is. My best solution so far is to use a generic cube for the physics and set it to phantom.

It's a wee paddling pool so not worth spending a lot for fancy physics on. (I haven't finished LODs yet so I don't know what the download LI will be but it should be low.) Any suggestions for what else to do? I know I could add a transparent prim to the base so the av's feet don't disappear.

Also while we're here, it's filled to nearly overflowing because that's where the rim verts were. I've been stingy with geometry, would it be worth adding another set so the water face can be lower down? It would be more realistic for sitting in, but not necessarily as a fish pond. I made it for the fish but I'm sure people will fancy joining them

[Aquila Kytori]

Hi Bitsy   Will the fish all have smiley faces ?

My first choice would be to make the collision surface using mesh. Keeping it as low poly as possible. In the screenshot below I started with a 8 vertice circle for the sides and a quad for the bottom of the pool. if you need to have the bottom raised up a little to allow for the thickness of the pool then use a second quad.

If the rim is small enough then you can get away without modelling that in the Physics model. A Physics model including a rim would probably double the final Physics cost because it would be made from small tris.

  I just checked and yes even with this "sharp" rim an avatar can still select and sit on the rim.

 

This physics model will not be Analyzed in the mesh Uploader.

Physics cost is very dependent on size !

Yes the water does look as if it is about to overflow . I think it worth the extra geometry to lower the level some.

 

Edited July 12, 2019 by Aquila Kytori

[Bitsy Buccaneer]

1 hour ago, Aquila Kytori said:

Hi Bitsy   Will the fish all have smiley faces ?

  I just checked and yes even with this "sharp" rim an avatar can still select and sit on the rim

Physics cost is very dependent on size !

Depends on what we put in the water.

Oooo. The physics rim in SL will be sturdier than in RL. I hadn't considered that 👼

Size will be on the order of 1m x 1m, though who knows what others might do with it if I put it up for sale. It's the small kind you keep in a shed and haul out to plonk a toddler or a dog in when it's hot. I'll go make one based on your suggestions and see what the cost is. Thank you so much x

(Correction 2.3 m x 2.3 m x .444 m)

Edited July 12, 2019 by Bitsy Buccaneer

[ChinRey]

10 minutes ago, Bitsy Buccaneer said:

Size will be on the order of 1m x 1m

If that means people are only supposed to be able to sit, not walk around inside it, You can simply use an analyzed filled-in octagon for physics. Sit positions and aniamtions are not affected by the physics shape in any way.

[Fionalein]

And don't forget - people will add their own scripted water / pool bottom prims themselves.

[Aquila Kytori]

24 minutes ago, Bitsy Buccaneer said:

Size will be on the order of 1m x 1m,

1 Meter ! ! ! ! 

I just rezzed a Physics model for that size ...........thats really very very "weeeee" lol .  maybe ok for fish pedicures but not to sit in .

This is using a hexagon instead of octagon as start for physics :

[Bitsy Buccaneer]

Still walking on water. My physics model looks (to my eyes at least) like Aquila's. It's an 8 vert cylinder in the same dimensions with a single plane underneath. Dimensions are 2.3 x 2.3 x .444, physics is 1.0

Shouldn't this physics model allow for standing in the pool? If nothing else, I'd like to learn how to do that as an option.

[Bitsy Buccaneer]

5 minutes ago, Aquila Kytori said:

1 Meter ! ! ! ! 

I just rezzed a Physics model for that size ...........thats really very very "weeeee" lol .  maybe ok for fish pedicures but not to sit in .

This is using a hexagon instead of octagon as start for physics :

It's 2.3 x 2.3.  I was sort of haphazardly guessing from the stretch out an arm for a yard way of guesstimating fabric length. Oops

[ChinRey]

2 minutes ago, Bitsy Buccaneer said:

Still walking on water. My physics model looks (to my eyes at least) like Aquila's. It's an 8 vert cylinder in the same dimensions with a single plane underneath. Dimensions are 2.3 x 2.3 x .444,

The dmensions are the problem there. Any object with a size less than 0.5 m along any axis is automatically converted to convex hull

[Aquila Kytori]

Have you changed the Physics Shape Type to Prim in the in the SL build floater > Features tab ?

and what Rey just said

Stretch it a bit along the Z axis untill it deeper than 0.5m

 

 

Edited July 12, 2019 by Aquila Kytori

[Bitsy Buccaneer]

Just now, ChinRey said:

The dmensions are the problem there. Any object with a size less than 0.5 m along any axis is automatically converted to convex hull

OK, I'll go change it inworld. I'd never have thought of that. Thanks Rey.

[Bitsy Buccaneer]

@ChinRey and @Aquila Kytori, bigger (over .5 m high) and prim now and it works. Viewer shows physics as .7, I'll try it six-sided instead. Feet are still in the floor but I can fiddle with that.

All your help is much appreciated. There are just so many things to remember.

[Aquila Kytori]

If you look carefully at my physics model it dosen't just have inside faces. It has outside faces as well, otherwise you may find that avatars can walk through the single surface "walls" into the pool.

[Bitsy Buccaneer]

3 minutes ago, Aquila Kytori said:

If you look carefully at my physics model it dosen't just have inside faces. It has outside faces as well, otherwise you may find that avatars can walk through the single surface "walls" into the pool.

I'd discovered that , and made one with inside walls, though not nicely sloped like yours. And then I spent way too long walking in and out of pools on the beta grid, getting a feel for the differences. My two sided one is about 1 in physics and the single sided hex is showing as .5 (both with two planes so the feet don't sink into the floor). I'm going to lower the water and work on the LODs, then I'll choose the physics based on the overall costs.

Prior to this, I've read dozens of threads about physics but never had a project to use it on. All that stuff rattling around in my head just complicated this wee project, but thanks to the help here I have a much better handle on it now, and in very short order too. We have such a valuable and tremendous resource here in the people who contribute their skills and knowledge. It is abundantly appreciated.

 

[ChinRey]

2 hours ago, Bitsy Buccaneer said:

And then I spent way too long walking in and out of pools

Be careful with that, it's a sure way to catch a cold!

Edited July 12, 2019 by ChinRey

[ChinRey]

I'm not allowed to totally agree with Aquila of course - that would set a bad presedent. Here's how I would have done the physics:

The difference is that I keep the bottom inside the pool. It only adds two triangles and the physics weight is only 1.0 at 2.3x2.3x0.6 m size.

It's a shame we can't have octagonal physics for this. Unfortunately the moment we do that, we end up in the 2 LI physics weight region with such a small size.

[Bitsy Buccaneer]

8 hours ago, ChinRey said:

I'm not allowed to totally agree with Aquila of course - that would set a bad presedent. Here's how I would have done the physics:

 

The difference is that I keep the bottom inside the pool. It only adds two triangles and the physics weight is only 1.0 at 2.3x2.3x0.6 m size.

It's a shame we can't have octagonal physics for this. Unfortunately the moment we do that, we end up in the 2 LI physics weight region with such a small size.

I will try this too. This has been good practice and learning for me.

Is the difference just that the triangles on an octagon become too small at this size? I was thinking about trying it squared off to see what the physics cost is and how it feels to walk into the invisible corners inworld.

[ChinRey]

3 hours ago, Bitsy Buccaneer said:

I will try this too.

The reason I suggest this alterantive is of coruse that it won't interfere with people standing outside the pool.

 

3 hours ago, Bitsy Buccaneer said:

Is the difference just that the triangles on an octagon become too small at this size?

No, there are just too many of them.

[VirtualKitten]

If you add your own scripts you can shrink higher the water when you get in even add splashes to give effect I wrote one for swimming polls based on  some converted fireworks same principle for a water splash launches from the point of contact.

Denise