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Jumbomahmo

Problem with home mesh

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hello all

sorry for the  inconvenience

Problem
Transparent House
Can breakthrough
I have worked all the solutions did not work

How to make it non-transparent (steel)
How to make (steel)
Watch the video

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why you make it convex hull? i have my yatch set to none so i can enter it and the house is phantom. you would still need to build up the entier house in prims inworld but just invisible walls on the inside.. the outside can be phantom.

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Hi :)

When making something like a mesh house you need to tell the mesh Uploader which parts of the mesh you want to be "physical" ,( which parts you want your avatar to interact with , like door openings , walls, floors and ceilings ). Then once you have rezzed your house inworld you need to change the Physics shape from ConvexHull to Prim. If you don't do this the uploader will use the ConvexHull method to create a collision physics shape for your house.

You can think of a ConvexHull shape as if someone has stretched clingfilm all over your house, closing all the openings .

The first image below shows you where to tell the uploader what shape to use for the Physics or your house

Physics.png

In Step 1 you would normally  create a seperate Physics mesh for your house and choose From File but just to get your house working and your house mesh is using very few vertices  you can choose High this time . This means it will use the same mesh for the physics as you use for the actuall mesh house.

In Step 2 hit Analyse.

When you have rezzed your house Inworld change the physics shape in the edit panel from the default ConvexHull to Prim.

Physics edit.png

Now you will be able to walk inside your house :)

 

You can see the physics shapes of things Inworld if from the Develop menu > Render Metadata you enable Physics Shapes.

Physics shapes.png

If you now rez your original house beside the new one you will be able to see the difference. Convex Hull you will see there is no openings and Prim type you will see the openings and the seperate walls .

It is never a good idea to rez your house on top or yourself or another avatar because then it will mess up the physics as you experienced in your video. Even thought it was ConvexHull it seems to be phantom !

Now all you need to learn is how to make your own mesh Physics shapes for future uploads :)

For buildings there are 2 types. One using  Flat plains (in which case you don't Analyse in Step 2 ) and the other using Non overlapping boxes ( Analyse in Step 2 of the uploader )

 

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me back again .....

I did some experiments using a Simple Mesh House (1) and created 2 Physics meshes for it  , using NON Overlapping Boxes (2) and simple Planes (3).Physics explained.png

Below is the result of Uploading the Simple Mesh House along with the different physics meshes . The most economic is the version that was uploaded with the Planes mesh used for Physics.

SL House Phys.png

I hope this helps you get some idea of what you should be trying to do .

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Thanks Aquila, for a very good tutorial and easy to understand :). Seems that using planes, not analysing and setting to prim is a good option but -

I'm trying to make physics for steps (stairs) using your guide here - planes for the step surfaces, no analysing and setting to prim. This does keep the shape of the steps better than when I analyse and set to convex hull as I don't float as much. But now I sink into the steps at first (almost like phantom) and then I get pushed up onto the surface. This spoils the natural walking surface I'm trying to achieve. The collision with the plane and prim physics has a sinking in and pushing out effect. Maybe using boxes for the physics will fix this but will also increase the LI which makes it not an answer either. Any advice here would be appreciated.

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hi

Re steps.... sorry but this is going to take up alot of space because i don't know how to reduce the size of the screenshots and keep image quality  :(

Experiments with physics for steps , first image is of the 10 steps in Blender :

steps.PNG

The next 2 images are of box type physics for the steps. The physics mesh and then the uploaded, Analyzed in step 2, rezzed Inworld and set to Physics type : PRIM in the edit panel, with show Physics enabled . steps Phys box.PNG

Steps box physics analyzed.PNG

As expected the Physics for the steps works perfectly but the LI = 4

Next 2 images are same steps but using simple planes for physics ( not Analyzed in step 2 )

steps Phys 1.PNG

steps planes 1.PNG

As you experienced LI is lower but the physics are bad because of the spaces between the planes.

Next I tried closing those spaces :

steps Phys 2.PNG

steps planes 2.PNG

While the physics was better the LI was higher .

So remembering something Drongle said about the uploader not liking small triangles I next tried enlarging the faces of the physics mesh :

steps Phys 3.PNG

steps panes large 1.PNG

This reduced the LI to 1 but if you were wanting free standing steps and so allow avatar to walk behind the steps aswell some of the physics plains would need to be smaller.

(Note in this version of the steps , the steps, highlighted in yellow, are not aligned properly with the physics for the lower steps because when I aligned all the lowest vertices to zero in the Z axis I forgot to then align them to the bottom of the lowest step, correcteted for last upload )

steps Phys 4.PNG

steps panes large 2.PNG

Again LI = 1

With more experimenting like closing the sides etc I am sure you will find a happy compromise bewteen physics and LI

But I think i should leave some for you to do yourself  :)

1 thing to mention, I think it best not to make the horizontal "depth" of the steps to small , seems like the larger the better

 

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Wow Aquila, thanks a lot!

I noticed that about the horizontal depth of the steps too, the deeper the better. My steps are meant for landscaping, not houses. They are meant to be pushed into the ground and so the back doesn't matter too much. I'm going to try this tomorrow and post my results here.

You're very good at keeping your explanations simple.


Aquila Kytori wrote:

 

(Note in this version of the steps , the steps, highlighted in yellow, are not aligned properly with the physics for the lower steps because when I aligned all the lowest vertices to zero in the Z axis I forgot to then align them to the bottom of the lowest step, correcteted for last upload )

 

This is a problem I have. My steps don't align with the physics model like it should when I view it at the upload stage. I'm going to try what you say here - aligning to zero in the z axis...work out how to do that.

 

Thanks again and I will let you know here how I go with it. :)

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I think you left out the most basic and probably best option for stairs physics. Just use a single sloped plane. For balls rolling down a stair it won't be the best representation, but for walking avatars it will be. No bump bump bump walking up the stairs and almost no load on the physics engine. A low landimpact isn't the only thing to aim for.

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OK, here are my results -

 

steps new.png

 

As you can see, it worked perfectly. Land Impact is 1.

Thanks again, Aquila :). This is really teaching me a lot about physics. I would never have thought that such complex physics would give such a low LI.

 

Oh, and using a sloped plane doesn't work for me. In the preview window it is always horizontal, and when uploaded it creates a barrier in front of the steps. Not sure why this happens to me. In Maya the plane is sloped perfectly to cover the steps.

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Rya Nitely wrote:

Oh, and using a sloped plane doesn't work for me. In the preview window it is always horizontal, and when uploaded it creates a barrier in front of the steps. Not sure why this happens to me. In Maya the plane is sloped perfectly to cover the steps.

My best guess is you didn't delete history or whatsitcalled in Maya. The rotation of the plane before export should read 0,0,0.

The result won't be as accurate visually as what you have now, but like I said before, the walk would be a lot smoother and it would be a lot easier on the physics engine.

What you have now btw, without intention I think, is a way to cheat the physics weight calculation. The planes are big, but they act as small ones, the only parts you'll ever touch are pretty small. Small means lots of collisions to the physics weight calculation, so that means a high landimpact. Making the planes bigger doesn't change the actual behaviour/load in any way, but it does lower the landimpact.

Instead of cheating you could call that being clever, that's up to you. I call it cheating:) Either way, the low landimpact is not a good representation of the actual load on the physics engine.

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hi Kwakkedle :)

Your quote:

"The superior man understands what is right; the inferior man understands what will sell." Confucius

is perfect here, lol.   No offence meant towards you Rya :)  but i thought that funny .

Cheating implies breaking of rules, being clever suggests being resourcefull. This came about by a step by step aproach to arrive at solution (as i explained in message 8 ) to a particular question and is just that, one solution . I never thought of it as a cheat and as Rya said most of it will be buried in the ground so the hidden physics shelves will be perfect for the worms to store their shoes on , so not wasted.

Yes i do agree with you that we should all try to do our bit to reduce lag but you must always remember that most of us are learning as we go along from people like you and Drongle and Chosen and all the others who actually know what they are talking about . Big thanks to you all . 

Thankyou

 

 

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I can only speak for myself, but am pretty sure Chosen and Drongle (and many others with more knowledge/experience/understanding than the average SL resident) also learn every day as well as any other person.

I explicitly mentioned "not intended", I'm sure this exercise wasn't ment to find any loopholes in the system. But the exercise might be done the wrong way. If you had started out with the problem, "I need to go up and forward" and had taken into account the number one rule of realtime rendering (or real time physics calculation in this case) "don't use more than you need", you might have ended up with a single plane yourself. It has its pros and cons, reducing lag is just one of the factors. As shown in the picture, you can stand on a single step, which isn't possible on the sloped plane. So if the stairs are for example placed in a meeting area and people will stand on it rather than walk, this might actually be the "best" way to do it.

As a sidenote, the physics shape doesn't have to be a simplification of the visible object. Recently I made some parts where the physical model had more geometry than the visible model. This was to get rid of the bump bump bump I mentioned earlier.

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Aquila Kytori wrote:

hi Kwakkedle
:)

Your quote:

"The superior man understands what is
right
; the inferior man understands what will
sell
." Confucius

is perfect here, lol.   

 

hehe I smiled when I read this too :). I only looked for an answer to the floating problem because of a customer complaint. And I always think when one customer complains there are others who are just biting their tongues. This customer said I should try to improve the physics. And hence I travelled down this road.

I was using a sloped box, my lowest LoD, for physics and I didn't see the floating as a problem until I was told. I'm a big avatar, this customer was a small girl and the floating was much more noticeable.

I'm going to revisit the plane and test on different size avatars...see how I go. Otherwise the worms will have nice bookshelves....maybe they're bookworms :P

I also want to say that I am very impressed with the help and quick responses in these threads. Big thanks to everyone :)

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Your physics mesh is one  of my top ten mesh images of 2012 , awesome,  lol

Now that I  have done the book cover you have no excuse not to write the guide :)

Definitive .png

HAPPY NEW YEAR to you all

 

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hehe :)... and by the way, I think you're a genius, and so does my partner. Believe me I worked on this for weeks and tried everything. Nothing worked but this. I'm actually starting to believe it's the only step physics that will work. Perhaps a tweak here and there, or one less plane, but basically this is the answer.

Happy New Year to you too :smileywink:

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