I have thought long and hard over this tutorial and what exactly I wanted to relay first. My main goal is to get you building in mesh as quickly as possible. I am also a strong believer in working in-world as much as possible. This tutorial is aimed at total beginners, so please be patient those of you with more advanced skills. I will be covering more interesting topics later.
Also, before I get going, I also want to say that if the idea of using a 3D design suite like Blender seems daunting, thats because it is. Its a lot of hard work sometimes, but very rewarding once you get past the initial learning curve. Everything I have learned I have done so by trial and error, watching tutorials and reading manuals. I started with rocks and just went from there, and of course, I am still learning too!
I am going to take you through this as slowly as possible, building on your knowledge step by step. Often, a task that seems near impossible is just a few well-informed clicks away from possibility. If I can save you just a small measure of the frustration I went through learning all this stuff, then this will be a job well done.
So, without further ado, here is the first installment of the series.
Part 1 - Creating a set of basic prims in Blender
a: Why use mesh prims?
b: Your first mesh prims
Part 2 - In-World Mesh Design using prims and shapes
So without further ado, here is Part 1.
Part 1 - Creating a set of basic prims in Blender
Why use mesh prims?
So first I would like to talk a little about why using mesh prims is in the interest of every sim owner. As some of you might already know, "in world prims" are also made from a mesh. "Mesh" as used commonly in virtual worlds is a slightly misleading term. A better term might be "externally designed geometry", but hey! Its not very snappy.
If you rez a prim and switch your viewer to wireframe mode, you will see that each prim is infact made up of triangles just like a mesh model. A typical square prim has 16 tris per face. It needs those tris to be able to deform using the parameters in the build menu. Trouble is, once you have deformed the prim to your liking, there is no way of getting rid of those unnecessary tris. They are always there.
A box with no deformation needs no more than 2 tris per face. See the example pictures below.
So, replacing as many prims with mesh equivalents can improve rez times and server load. If you are building a complex world, the benefits can be very significant. Furthermore, I believe many people will find it beneficial to be able to build with mesh prims in-world. I am comfortable sculpting and designing entirely in a 3D app, but the thought of making something huge like a house or castle is still rather daunting, even to me.
Also, in my experience of structures made of mesh that have been designed entirely externally, they tend to feel "off" somehow. Either in scale, or they feel paper thin or look somehow out of place. Designing in world helps get the feel just right. Plus building in this modular way means you can go back and re-use and modify designs in-world easily, and there is nothing stopping you at any point exporting your in-world work for tweaking and optimization as you wish.
So, how do we make them?
Your first mesh prims
Thankfully, Blender has a number of "system prims" available to us, and we need to do very little before we can start using them.
Some of you will no doubt have tried to just import the initial Blender cube and wondered why it does not texture in the same way a prim does. Your about to find out why
.I would recommend using the cube given at the beginning. If you look at the prims available in SL, you will notice that all of them can be achieved with a cube, cylinder and torvus shapes. These are all available to you by pressing CTRL+A and selecting from the “mesh” section of the drop down.
Firstly, we need to define each individual face we want to be a texturable surface in-world. Opensim/SL supports no more than 8 texturable faces per mesh. If you go over that limit, the faces with material 9+ on them will appear invisible.
So, go to edit mode (TAB) and then CTRL+Tab and select "face".
Highlight the first face and go to the materials controller in the top right corner. You will notice there is already a material listed. This material currently covers every face of the prim.
To add a new material to the face, Click the + button to define a new material slot.
Then click "New" and "assign". Your new material will be assigned to that face and its surface will become texturable separately from the rest of the cube. Here I just changed the colour.....
Repeat this step for each face of the cube. When your done, export as a DAE file.
Now import the prim in-world, selecting the highest physics model possible. Normally, this is a no-no, but for models this simple, this method is acceptable. The physics model will only be as complex as the original mesh. Incidentally, it is by combining simple geometry like this that we make physics models. Even very complex models have a simple underlying model used for physics. So when we are using these simple building blocks, physics models and LOD are not necessary. Also replace the LOD numbers in the "medium" and "low" columns with the original poly count shown in the “highest” row in the uploader screen. Set the "lowest" row to Zero. This LOD stage is unnecessarey for most things which are not very small. Smaller objects can benefit from this LOD stage.
Now select a texture from your inventory. It will look like a single block of colour, but we can fix this by going to the texture tab and changing the mapping from "default" to "planear" and setting the vertical and horizontal offsets to between 0.1-0.3 depending on the texture. That is how you UV map in-world.
So now you have your first mesh prim!
Taking it further – Editing Default prims
Ok, so now we understand the basics of texturing and importing, lets get more into creating custom prims for your exact needs. Obviously to do that, we can look back to the tutorial I posted on Blender Basics previously. If you covered this, chances are you already have some ideas about how you can now modify these shapes. There is a huge array of things which can be done. I will show you now something fairly simple (tapering a cube), for the sake of brevity, I will follow the this tutorial up with something more advanced like cutting holes or an arch later.
Now, obviously, we can do this by simply selecting the verts and physically moving them with the mouse, but we want to be much more precise than that. So select the verts as shown below, then move them just slightly. You will hopefully notice the “Translate” control pop up in the bottom left hand side of the screen. We want to translate these verts along the green Y axis. Lets shave off 0.5. Type this value into the Y axis vector box. Your verts will then snap to that location.
Select the opposite verts and repeat. Remember to nudge the verts slightly with the mouse. For some reason blender does not auto-switch to the new values. That could be a bug.
Because we want to move the other verts in the opposite direction, we will add a negative value of -0.5 this time.
We now have a prim tapered 50% at the top. It might look a little wonky in this view, but press 7 or 3 on your numberpad to snap to Orthographic view and you will see its perfect.
For more on perspective and Orthographic view, see:
http://wiki.blender.org/index.php/Doc:2 ... ng/3D_View
Whew, so there we go
. You can play with the translate parameters and create a wide variety of basic prim shapes. make sure each side has a material and away you go! Using the translate hotkeys with a vertex selected and moving your mouse around can help you create some more bizarre shapes.http://wiki.blender.org/index.php/Doc:2 ... ion,_Scale
Next time I will cover making some slightly more intricate shapes, starting with a common architectural feature - arches.
and of course, feel free to post any questions below or PM me directly if your shy
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doh. lol I will update the tutorial.