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Trinity Fullstop

Does anyone build with prims anymore

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2 hours ago, Macrocosm Draegonne said:

I love prims for quick prototyping.

There's another related reason for building with prims.

This is what I'm buiding at the moment:

https://community.secondlife.com/forums/topic/429205-structural-construction-question/

It's a reconstruction of an old building, based only on a few vague photos. It'll be mesh eventually of course but by starting with a prim version, I was able to walk around it, on it and inside it and I could see it in a landscape. It's amazing how many details became obvious that way, details it would have been very difficult to get right if I had worked in a sterile Blender window from the start.

Edited by ChinRey
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1 hour ago, ChinRey said:

There's another related reason for building with prims.

This is what I'm buiding at the moment:

https://community.secondlife.com/forums/topic/429205-structural-construction-question/

It's a reconstruction of an old building, based only on a few vague photos. It'll be msh eventually of course but by starting with a prim version, I was able to walk around it, on it and inside it and I could see it in a landscape. It's amazing how many details became obvious that way, details it would have been very difficult to get right if I had worked in a sterile Blender window from the start.

So true!  To get a sense of space from first person perspective can be infinitely useful! 

Im waiting for Blender 2.8 to try it, but, I think there are some ways we can approximate the SL environment from within Blender and the real time rendering EVEE stuff.    That way using fly/walk navigation could prove to be even more useful, and it would feel like meshing in world.

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There's a prim to mesh converter on Marketplace, but I gather it's not very good. Would a better one be useful?

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13 hours ago, animats said:

There's a prim to mesh converter on Marketplace, but I gather it's not very good. Would a better one be useful?

There are at least three of them.

One of them (i can't remember the name right now) has a depressing tendency to create duplicate overlapping triangles and that won't do of course. The other two, Mesh Studio and Mesh Generator, can make very decent meshes if you know how to. It's not straight forward though, it takes a lot of understanding how mesh works and some outside-the-box thinking to make good LoD models.

Edited by ChinRey
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23 hours ago, ChinRey said:

There are at least three of them.

One of them (i can't remember the name right now) has a depressing tendency to create duplicate overlapping triangles and that won't do of course. The other two, Mesh Studio and Mesh Generator, can make very decent meshes if you know how to. It's not straight forward though, it takes a lot of understanding how mesh works and some outside-the-box thinking to make good LoD models.

I find the prospects of converting prims to mesh nearly useless, wont that be high li and iffy lod comparatively?  The prims cull vertices and lod and all the things really well.  So if you can make it from prims & it looks great may as well leave it prims IMO.  Aside from prototyping of course, but all you need for that is firestorm or other viewers that let you download the prims as objects for 3d party apps. 

I also use an old sculpty/prim robot trick, (that now can output mesh instead) for scanning terrain to clone a base to build on in blender. :) 

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@ChinRey

I use Mesh Studio, and while I know I am only scrtaching the surface, the basics are quite simple, there are some real good tutorials, in general I swear by it.

@Macrocosm Draegonne

To the contrary, converting to mesh can save tonnes on LI. As mentioned, I use Mesh Studio and am sure I could get even better results were I to study it a bit more, it saves me 100's of LI on builds. Some recent examples:

Detailed Front Door - 70 prims, 35 LI as joined ConvexHull, 3 LI when Meshed

Elevator - 138 prims, 69 LI as joined ConvexHull, 6 LI when Meshed

Overall on current build, various pieces, 1342 prims, 674 LI as joined ConvexHull, 85 Li when meshed

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2 hours ago, Wandering Soulstar said:

I use Mesh Studio, and while I know I am only scrtaching the surface, the basics are quite simple, there are some real good tutorials, in general I swear by it.

That's how I started with mesh too and I still use Mesh Studio a lot to transfer my prim prototypes to Blender. The LoD models are the main reason I don't upload meshes directly from Mesh Studio anymore. It is possible to make good LoD models with Mesh studio but it can be a horrendous amount of work. Much easier to import to Blender and simplify there and of course, once the model is in Blender, you might as well do a few other tweaks too, like closing the prim gaps, improving the UV map, add a some extra details...

 

2 hours ago, Wandering Soulstar said:

Detailed Front Door - 70 prims, 35 LI as joined ConvexHull, 3 LI when Meshed

The limiting factor for prims when it coems to performance, is nearly always the assets server. Each prim is stored as a separate entry in the database and with almost 30 billions entries, it's bound to take a bit of time to find them all. This is why linksets with many prims have such high land impact.

The amount of data that is transferred is always much lower for prims than for mesh and once it's reached the viewer, a well amde prim build will easily outperform any but the very best optimized meshes.

 

14 hours ago, Macrocosm Draegonne said:

Aside from prototyping of course, but all you need for that is firestorm or other viewers that let you download the prims as objects for 3d party apps.

The difference between the prim-to-dae converters built into Fs and the lsl scripted ones like Mesh Studio, is that the viewer ones export each prim as a separate mesh and that means it's completely useless if you want to reimport directly.

Lsl based converters merge an entire linkset into a single mesh and that is the only reason why it may make sense to convert prims to mesh.

Edited by ChinRey
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28 minutes ago, ChinRey said:

It is possible to make good LoD models with Mesh studio but it can be a horrendous amount of work. Much easier to import to Blender and simplify there and of course, once the model is in Blender, you might as well do a few other tweaks too, like closing the prim gaps, improving the UV map, add a some extra details.

Hmmm .. well when I have the time to learn will have to make a try for the jump to Blender to improve my meshed prim builds.

 

29 minutes ago, ChinRey said:

The limiting factor for prims when it coems to performance, is nearly always the assets server. Each prim is stored as a separate entry in the database and with almost 30 billions entries, it's bound to take a bit of time to find them all. This is why linksets with many prims have such high land impact.

The amount of data that is transferred is always much lower for prims than for mesh and once it's reached the viewer, a well amde prim build will easily outperform any but the very best optimized meshes.

I do not get what you are saying here @ChinRey. First off, with prims set at Convex Hull, 2 prims are only one LI, so 1/2 that of two unlinked prims, so your statement on a linkset having a high LI confuses me.

And while I understand the data transfer part, from a LI perspective (i.e. how much I can have on my parcel) Mesh beats prims by miles ... if I was not to have meshed the various portions of my build it would have been near 1000 LI, not leaving me much space to furnish ?

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1 hour ago, Wandering Soulstar said:

I do not get what you are saying here @ChinRey. First off, with prims set at Convex Hull, 2 prims are only one LI, so 1/2 that of two unlinked prims, so your statement on a linkset having a high LI confuses me.

No wonder. I think the LI system was specially made to be as confusing as possible.

Land impact is an attempt to measure how much workload an item adds to Linden Lab's servers and connection lines and there are two different ways to calculate it.

The old way was simply to count the number of prims: one prim equals one LI.

This was too simple and imprecise in the long run and when mesh was introduced, they switched to a new system based on three "weights". That caused a bit of a problem with old builds. Most of them have the same or lower land impact with the new system but a few ends up with much higher LI. The solution LL went for was to keep both systems:

  • A build that could have been made before the new LI system was introduced, has its land impact calculated the old way
  • Any build that includes one or more features that was added after the new LI system, is calculated the new way.

The convex hull is one of those newer features. The convex hull trick is usually not about changing anything significant, it's just a way to force the land impact to be calculated the new way.

---

Those weights the new system is based on, is calculated from how much load the objects adds to various parts of LL's system. There are three parts there:

  • The assets servers have a database listing everything in Second Life. When an object is needed, it has to search for every part of it in the database. The work it has to do, is the server weight.
    • Each prim, mesh and sculpt in a linkset adds 0.5 to the server weight
    • Each active script in the object  adds 0.25 to the server weight
  • The sim server handles everything that happens in the sim. It has a lot of work to do but most of it is not directly related to a specific object. The one important exception, is the physics. So the workload an object adds to the sim server is only based on how complex the physics model is and it's called physics weight.
  • Once the server have done their job, the data has to be transferred to your viewer. That is the download weight and it's simply an estimate how much data there is to transfer.

Now, no chain is stronger than its weakest link of course, so rather than add up all those three weights to determine the land impact, LL decided to make the highest of the three count. That has some interesting consequences:

  • A single mesh doesn't give the assets servers much work, they only have to find one entry in the database. Meshes need a lot of data to be transferred though, so the download weight can be quite high. The result is that it's usually the download weight that counts as the land impact for meshes.
  • The same shape made from a linkset of several prims doesn't require much data to be transferred at all so the download weight hardly matters. But the assets servers have to search for each and every one of those prims. That's a lot of work, so for prim builds it's the server weight, not the download weight that determines the land impact.

(Unless the physics weight is higher than both the server and dowload weights of course, but that's another story.)

The idea with converting prims to mesh, is to reduce the server weight at the cost of increasing the download weight.

As for the convex hull trick, a single prim still only counts as 0.5 LI according to the new system, half of what it is according to the old system (again, ignoring physics weight), so there's quite a lot to save there and it's very easy to do.

Edited by ChinRey
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6 hours ago, ChinRey said:

The difference between the prim-to-dae converters built into Fs and the lsl scripted ones like Mesh Studio, is that the viewer ones export each prim as a separate mesh and that means it's completely useless if you want to reimport directly.

Lsl based converters merge an entire linkset into a single mesh and that is the only reason why it may make sense to convert prims to mesh.

Yea, its far too many tri's and not really the best topology for much, but it can be fixed quickly, or just left there in blender as a guide for making fresh clean mesh.  I did take a look at mesh studio, but by the time I found it I already had a good working knowledge of Blender, so for me Id rather be responsible for all the vertices and not have to clean things up which can often take more time than building things from scratch.

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prim to .dae convertors are quite useful as a learning tool for people who know how to build with prims and want to learn Blender etc

can export a prim build, import it into Blender etc using it as a reference. Because we built it then we know what it is we want to see in Blender etc.  We can use this knowledge/understanding of our own build to start working out which buttons to press to mod/reduce/.torture it

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On 8/23/2018 at 2:08 PM, Trinity Fullstop said:

Wondering if anyone builds with prims anymore. The old fashioned way - inworld , upload textures - all that historic stuff. Just wondering :-)

Yes, that's the only way I ever built stuff, I have one building alone on one of my OpenSim regions that is 8,800 prims, the region is set to handle 100,000 prims and it runs off a Mac Pro quad core in my basement that I am using as the server for the sims. The build is of the University of Idaho's admin building, and the next to the last photo is inside what I call the "Great Hall" It took about 6 months to build the sim in 2011. The last photo is inside the library with it's barrel vaulted ceiling.

 

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Edited by Doggie Jigsaw
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On ‎8‎/‎23‎/‎2018 at 9:08 PM, Trinity Fullstop said:

Wondering if anyone builds with prims anymore. The old fashioned way - inworld , upload textures - all that historic stuff. Just wondering :-)

While I do the final products for my store in mesh, I do most of the initial designing inworld with prims. It helps to get a good feel of proportion and perspective. I then make the item in blender using the inworld prim mock up version for measurements. Working this way keeps the creative aspect of building in SL and that is important to me. It is also easier to keep up social stuff when not having to switch from blender to SL for each IM. Whenever I need a simple shape for an event display or for my store I tend to use good old prims as well. And lets be honest, there is just something about building inworld with prims. It is deeply satisfying and what got me excited in SL in the first place….

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