blender vs SL, help a newbie out

[Akary Nyoki]

So I started to mess around with blender, watched some tutorials on youtube and started building my first ever mesh object. At first I was doing extremely detailed mesh when I realized that maybe SL wouldn't be able to handle too many vertices/faces. So I've been making/deleting over and over without much knowledge on what to aim for when importing it into SL.

The project is some kind of bracelet and I'll add more details to it later. To start building it I actually made a cilinder in SL that would fit my avatar, imported it into blender and made it the same size. Now here's some of my questions (I haven't uploaded anything inworld yet).

01. If I use more than one object in blender and link them together, does that counts as 1 or multiple prims in SL?

02. Should I add physics to this or it doesn't matter? (since it's an accessory)

03. Since I got the sizing imported from SL, is it gonna be the right size when exported back or should I also mess with the scaling tab when uploading?

04. I added some pictures in this post, showing the blender project and the SL upload window. Is there any threshold or suggestions on the numbers shown? (such as land impact, download, physics, triangles, etc).

I'm sorry if these are explained elsewhere, but as I searched the internet for answers it always seemed to be a bit confusing. Or guides of "less quality mesh" (SL specific), which I would judge outdated. Maybe I'm wrong.

I'm very new to 3d building but I'm eager to learn so any links would be appreciated. (I finished the blender donut tutorial level 1 and 2).

By the way, when I click on different LoDs in the upload window it barely looks round, only High seems to fit properly (even after triangulating). Not sure it's an issue.

 

[Chic Aeon]

12 minutes ago, Akary Nyoki said:

So I started to mess around with blender, watched some tutorials on youtube and started building my first ever mesh object. At first I was doing extremely detailed mesh when I realized that maybe SL wouldn't be able to handle too many vertices/faces. So I've been making/deleting over and over without much knowledge on what to aim for when importing it into SL.

The project is some kind of bracelet and I'll add more details to it later. To start building it I actually made a cilinder in SL that would fit my avatar, imported it into blender and made it the same size. Now here's some of my questions (I haven't uploaded anything inworld yet).

01. If I use more than one object in blender and link them together, does that counts as 1 or multiple prims in SL?

It will be ONE object. It could easily be more than one land impact (worn objects aren't counted that way but you still want to make worn objects as efficient as possible).  And you you DO want to "join" your objects in Blender before uploading (in most cases). 

12 minutes ago, Akary Nyoki said:

02. Should I add physics to this or it doesn't matter? (since it's an accessory)

 

You should always use your own physics model (again 90 percent plus of the time) even if it is just a cube. Having the uploader do this can cause all kinds of issue. On a bracelet it really won't matter but might as well start doing things with "best practices" in mind.

 

12 minutes ago, Akary Nyoki said:

03. Since I got the sizing imported from SL, is it gonna be the right size when exported back or should I also mess with the scaling tab when uploading?

It will be the same size as long as you don't change things when uploading. That bracelet may not fit all avatars in SL of course but it can be resized once in world.  

12 minutes ago, Akary Nyoki said:

04. I added some pictures in this post, showing the blender project and the SL upload window. Is there any threshold or suggestions on the numbers shown? (such as land impact, download, physics, triangles, etc).

That is certainly an acceptable model as it but you could easily remove the inside horizontal edge loop (and possibly the outside horizontal edge loop also) as the don't appear to be doing anything.  Deleting any vertices that don't actually change the shape of the model is always a good thing.   Just keep things as simple as you can  to make the shape of the model.  Textures can add a lot to the VISUAL shape. 

12 minutes ago, Akary Nyoki said:

I'm sorry if these are explained elsewhere, but as I searched the internet for answers it always seemed to be a bit confusing. Or guides of "less quality mesh" (SL specific), which I would judge outdated. Maybe I'm wrong.

You want to make "game asset" quality mesh for SL. There is plenty of NON- game asset (heavy and lag inducing) mesh in SL, but you want simplified mesh that is easy for everyone to see.  You can decide later on if you are actually in that "game asset" camp (plenty of popular creators are not and that is why folks have so many computer issues in SL (or one of the main reasons anyway). 

12 minutes ago, Akary Nyoki said:

I'm very new to 3d building but I'm eager to learn so any links would be appreciated. (I finished the blender donut tutorial level 1 and 2).

I have a full set of tutorials for Blender in SL. They are in Blender 2.79 though so if you are using the newer interface they might be confusing.  Just type in Chic Aeon Blender Youtube and you will find them if needed :D. 

12 minutes ago, Akary Nyoki said:

By the way, when I click on different LoDs in the upload window it barely looks round, only High seems to fit properly (even after triangulating). Not sure it's an issue.

YES  it is an issue.  That most likely means that your bracelet will deform when seen from a short distance. You don't want that.  For something as small as this you probably want to use the "Use LoD above" choice on at least the medium and the lowest.  You will need to test inworld. 

 

12 minutes ago, Akary Nyoki said:

 

 

[Quarrel Kukulcan]

5 hours ago, Akary Nyoki said:

02. Should I add physics to this or it doesn't matter? (since it's an accessory)

Every object will have a physics mesh, but it's ignored on attachments, plus most world-placed objects only need a simple cube (and even then, only if you care about not letting people walk through them). Simpler is better. A cube or single triangle are all you need unless you're doing something like a chair, or a whole building, or something for a combat sim. Model a cube and a triangle, export them to their own simple files, and just use them over and over as the physics meshes for your other projects. (The exact sizes don't matter because the physics mesh gets scaled to auto-fit the object's bounding box.)

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03. Since I got the sizing imported from SL, is it gonna be the right size when exported back or should I also mess with the scaling tab when uploading?

Blender import default scale is 1 unit = 1 meter in SL. Match that and you can avoid the need to adjust the scaling tab, which means one less step to mess up by accident.

One point of information: no object in SL can have a width, height or depth less than 1 cm. If you upload an object with smaller dimensions, SL will upscale the whole thing until the shortest dimension meets the minimum. You can't break this rule with the scaling tab (and can't shrink the object below that size in SL's edit mode, either). This will definitely hit you if you make small jewelry like rings -- you'll need to make them at an angle or put an invisible cube around them or something to get the bounding box size up.

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04. I added some pictures in this post, showing the blender project and the SL upload window. Is there any threshold or suggestions on the numbers shown? (such as land impact, download, physics, triangles, etc).

Just get them as low as you can (and understand that it takes professional-level skill to get LI -- the one that matters most -- really low).

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By the way, when I click on different LoDs in the upload window it barely looks round, only High seems to fit properly (even after triangulating).

Every object will have four Levels of Detail: the original plus three lower ones. Second Life makes those three for you if you don't make them yourself. It's pretty bad at it, though you can tweak it a little. The best long-term solution is to develop the skill of making your own. Like Chic already mentioned, this gets out of the realm of "making something in Blender" and into "making an efficient asset for one specific 3D game engine", so it won't be covered in Blender tutorials. Don't despair!

Forcing SL to re-use higher LODs for lower ones is one way to prevent bad auto-decimation, but you'll have higher upload costs, and people who wear the item will have higher rendering complexities and possibly get rendered on fewer players' screens. Going too far in that direction defeats the entire purpose of SL having an LoD system.

(One last thing I learned about Blender the hard way: whether you "Shade Smooth" or "Shade Flat" an object matters.)

Edited November 15, 2020 by Quarrel Kukulcan

[Akary Nyoki]

Thank you for your responses and clarifications. I'll keep studying and developing my skills. You helped greatly already.

5 hours ago, Chic Aeon said:

I have a full set of tutorials for Blender in SL. They are in Blender 2.79 though so if you are using the newer interface they might be confusing.  Just type in Chic Aeon Blender Youtube and you will find them if needed :D. 

I'm using blender 2.90.1 and I'm still getting used to all the functions and hotkeys, but I'll definately watch that! I've learned that you can browse functions with F3 so it shouldn't be a big issue.

[Cyrule Adder]

This is a good week or so later. but I want to add in a few more details for you later that hasn't already been mentioned in the answers above.

Firstly, and this will probably become important for you later as you start playing around with blender's sculpting functions to make more detailed jewelry. Generally, you only want to use as many polygons as necessary to correctly display your model at their intended viewing distances and importance. This distance varies massively based on the object's size. For example, you shouldn't need to use 3000 polygons on a button if you are viewing it from a meter away. You probably wouldn't even need 200 at the distance it would take to fill the screen. Basically... anything that adds definitely volume to an object most likely need the polygons to help define the shape. And how big those polygons can get can get pretty technical.

That being said... when you start sculpting, you will will have a massive amount of polygons. Fortunately you can simply encase that sculpt for jewlery in simpler geometry and use blender's internal tools to create a normal. These normals will make an object appear far more detailed than what they really are. Even make objects appear to be more rounded than normal.

 

1. There are some cases in when it is better to not join objects together. If you want objects to be more easily scaled to better fit a model, or perhaps customized by the user, then uploading objects unjoined is definitely not bad if the components needs to maintain a size to look reasonable. Another option when you might not want to join objects is when you make more complicated objects like avatars, cars, homes, etc. Prim count no longer matters in second life, it's now Land impact. Which land impact can change for the better or worst if you join objects. This will need to be something for you to ask yourself, but land impact is something you don't need to concern yourself with over accessories.

4. LODs are something that's very important, but often times just ignored by devlopers which causes massive framerate issues for second life. As well as visual problems. If you place your Mesh LOD to the default value, which I believe is one. You will see that a lot of objects in the SL world will suddenly either disappear or look like garbage. What happens is many developers will simply upload a single triangle for an LOD and expect users to set their LOD settings to the max.

The LOD basically means that as your camera gets further and further away from an object, it swaps to each level. Each level is expected to have a much lower polygon count making it easier to render. Because an object only takes up 20 pixels on your screen, you probably don't need to render a triangle that's only half a fraction of a pixel, right? And that trinagle has a massive cost for rendering on only a single pixel.

So... here's an example of a good LOD design. You have a furry SL avatar with ear piercings and teeth which you can easily see at about two meters.  Fifteen meters away those details are so small they are almost invisible. So the developer, being the mindful dev he is, decided that he should delete the polygons for the teeth as well as the piercings, and maybe even delete the toes of his feet or greatly simplified them to ps2 levels.

 

In your case. Your model is incredibly low in polygon costs. You can honestly get away with using the same model for multiple levels. But if that model hits... say 1k polygons, You would want to look into making LODs.