Ethos Erlanger's First Virtual Life© Blog

Building in Virtual Worlds

Archive for the ‘Tutorials’ Category

The BuilderCam by Erlanger Design

Posted by Ethos Erlanger on May 19, 2009

The BuilderCam TourCam is a HUD that I designed to allow you to walk through Second Life and look in the direction you are walking or facing from the vantage point and at the exact same level as your avatar’s eyes.

The home in this video is displayed in Second Life on Architecture Island by Crescendo Design.  I recorded this video using a HUD that I designed called a BuilderCam TourCam. The idea of this camera is that it allows you to view in front of the avatar as you walk and still have the use of your mouse for any normal activity you would use your mouse for such as touching objects, opening doors or editing an object.

Other uses I have found for the BuilderCam TourCam include building. This HUD provides a convenient way to work without having your avatar get between you and your work. Flying is possible with this cam but not as fully functional as without it. The BuilderCam TourCam is really intended for walking and level-ground standing avatar use.

Slow walking can be achieved by holding the space bar down as you walk. Try it and see how you like the slow-motion feeling you get. You will need to let up on the space bar to go up stairs or any inclined surface.

Arrangements are being made to freely distribute this BuilderCam TourCam at Architecture Island.


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Building an Octagon Roof In Second Life

Posted by Ethos Erlanger on May 10, 2009

Creating an Octagon Roof in Second Life

There are scripted tools available in Second Life to position prims, but this tutorial is intended to allow you to build the octagon using only the construction methods available from Linden Labs in their standard SL viewer.

I start by planning the size of the roof based on the size of the building.

This tutorial describes only one case of the octagon roof where I will use only eight prims for the roof.  This tutorial will focus on the basics that allow you to make a roof from 8 prims that could make any size up to a maximum of 17.32 meters across from side to side. If you need an octagon roof that is larger, then you will need to use more prims than the 8 shown in this tutorial. In another follow-up tutorial, I will show a more general case where the size can be made larger than I can make from 8 prims. you will need 24 prims or even more to make roofs of larger sizes, but the method requires a few additional steps, and the prim shapes are not all the same for the larger roofs.

The roof configuration I chose for this tutorial was made due to its general good appearance regarding the slope of the roof.  It is based on the roof slope of 30 degrees up from the horizon.  This is not generally the way a carpenter would build a roof in the USA, and I am unfamiliar with how roof rafter layout is done in the rest of the world where metric dimensions are used.  Most carpentry that is done with standard rafters by carpenters (and not made using factory-made wooden trusses) would describe a roof in terms of its rise and run. A roof that is a 6/12 pitch would be 6 inches high for every 12 inches measured along the bottom of the roof or the top of the ceiling. (The horizontal plane.)

Let’s start with the octagon that we have already built in our first tutorial about the octagon building.  This octagon has a wall length of 4 meters. We need to know the distance from the center of this octagon to the outer surface of the octagon.  We could use the trigonometric functions to learn this, but I will show you how to let the Second Life user interface give you this distance.

Set your octagon with its center at a whole number location on the coordinates of you sim.  I have chosen 100, and 100.  I do this so that the location of the individual prims is easily learned by subtracting 100 from its coordinates on the grid.  From its location on the grid, we quickly know the distance from the center of the octagon if it were measured along a straight line on the grid.

Find one face of the octagon that is perpendicular to either the x axis or the y axis. Offset this prim by half its thickness. Now the location of the center will read where the outer surface had been.  This dimension is useful in making your choice of the roof size for this building.

Let’s say you choose your roof to overhang the walls by exactly 0.5 meter, then you can simply add 0.5 meter to the value found in the preceding step. Or, again you could offset the wall prim used in the preceding step by one full thickness of the 0.5 meter thick wall.  This again allows you to know the distance from the center by reading it directly from the edit window.

The dimension you choose is your choice. You can make this decision of the length for this dimension and the method of construction will remain unaffected.

From your chosen dimension, you will first determine the length of the roof edge of one of the 8 roof segments.  The formula used is based on the Trigonometric function for a right triangle with a 22.5 degree angle.

The formula for the roof segment edges L1 is as follows:

L1 = 2 x (Base Length x Tangent (22.5deg))

For a Base Length of 5.5 meters, the Roof edge is 4.556349186 meters

Enter this value with at least 7  digits after the decimal place. While the build window only shows three digits, the SL system records several more digits that are not shown. This extra accuracy will benefit you in how close the prims edges come to each other. ( I continue to discuss with knowledgeable people how many decimal places are really of value for the accuracy we need for this type of construction, and the answer varies from 5 to 7 decimal places.)

Now, from the same base length we can determine the roof segment’s longest dimension L2. We will place the roof at a 30 degree angel from the horizon so, the formula for the long dimension is:

L2 = Base Length / Cosine 30deg. Again, enter this value with 6 or 8 digits after the decimal place.

See the video here:

Video Tutorial of Building an Octagon Roof in Second LifeThere is no narration, so continue to read the explanation that follows.

1)    Create and position the first roof segment.

2)    The Roof’s Edge length L1 will be the X dimension of the prim.

3)    The Roof Segment’s long dimension L2 will be to the Z dimension. The Y dimension is the roof thickness and again, just like the octagon walls, we will make it 0.5 meter thick.

4)    Taper this prim along the X axis to the full 1.00 value.

5)    Place this prim at the same center as we chose for the octagon walls. In my case it is X=100, Y=100, Z= 2,104.

6)    Now rotate this prim along it’s Y axis by 60 degrees.  The reason we use 60 degrees for this rotation, is that it is measured from the vertical position as it was built.

7)    Now Make a copy by the shift drag method along the Z axis and bring it up to any height above the first prim.  Now, rotate it around the Z axis by 45 degrees and then drop it back into place at the same height as the first prim.

8)    Repeat this process 6 more times.

9)    As you can see, we have been building along the construction lines that define our roof’s top surface and the centerline of each of our roof segments is on that construction line until we shift it ½ the prim thickness down along the normal line that is perpendicular to the roof surface.

10)    With all prims at the same height, change to local ruler mode, and shift each of the roof segments down to their 50% location along the local ruler.

I have tested these steps and used them to build a number octagon roofs.  If you experience difficulty with these steps, then it is entirely my difficulty in communicating their intent.

Some time soon, I hope to make a video tutorial for these steps which will surely be easier to comprehend when you see it in a visual form.

Posted in Education in Second Life, Second Life, Tutorials, Virtual Architecture | Tagged: , , , , | 1 Comment »

C.O.R.R. Construction in Virtual Worlds

Posted by Ethos Erlanger on May 1, 2009

C.O.R.R. (Center line, Offset, Rotation, Reference)

While I was preparing the tutorial for the octagon building, I wanted a way to define what it was I was showing the viewers.  In the virtual world that is built with the Prim, we must build objects with some limitations in the tools and techniques.  Wonderfully scripted tools have become available from gifted authors to aid us in prim positioning and sizing, but these scripts can also slow us down with many operations and turn into an unneeded crutch.

For building geometric shapes like buildings, as opposed to organic shapes such as trees and rocks, I position prims based on the distance each prim is from the center of the adjacent prim. Therefore I build along the Center Line of the prim.  This concept may be the most difficult for many of us to become accustomed to, who are emigrants to the metaverse from the terraverse. We are simply accustomed to measuring to the edge of an object such as a table or the walls of our homes.  Now it seems we must always be thinking: “where is the center of of the prim.”  When you get used to this concept, you will find building in the metaverse will become easier and faster.

To locate a prim based on the edge or face of the prim I Offset the prim by 50% of its width from its center.

To place a prim at an angle to the construction line, I Rotate the prim around its center.

To position a prim in relationship to the center or edge of any other prim, I use the Reference prim as the tool to locate other prims.

As you build geometrically shaped objects and buildings in the virtual world you will find these terms are at the CORR of you techniques for almost all of your prim placement.

As you view tutorials by me or other builders, think in terms of the CORR positions and movements.  With these concepts in mind, you will more quickly understand what you need to do as you build your virtual world.

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Octagon Building Tutorial – Why Double The Wall Width?

Posted by Ethos Erlanger on May 1, 2009

I knew this question would come up.  I just was not sure how best to explain the need for doubling the wall width when building the octagon walls.  Thanks to Ty Jaehun for the dialogue on this topic which helped me understand the simple explanation. I knew why, but I just did not know how to explain why.

Because this method of building the Octagon relies on the rotation of prims around the center (actually the centroid) of the prim and that rotation must be at a point found on the construction line of our building’s walls, the prim must fall on the construction line at it’s center;  so the wall edge is half the wall width away from the center of the prim and ultimately must be moved back to the construction line (center of prim).  I hate double-speak, so if there are any teachers/mathematicians out there who have a more concise way to explain this, let me know.  THANKS!

Doubling the words will never double the understanding. Ethos Erlanger

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Octagon Building Tutorial – Finally Complete

Posted by Ethos Erlanger on May 1, 2009

This tutorial is the first by Ethos Erlanger.  I hope this is is just the beginning and not simply a one-hit wonder.

Octagon Building Tutorial

The videos that preceded this final version are now gone from the YouTube site. I just hope I did not break any links to the older partially complete tutorial and disappoint anyone in the process.

Posted in 4 - Virtual Architecture, Education in Second Life, Machinima, Second Life, Tutorials, Videos on YouTube | Tagged: , , , , , , | Leave a Comment »

Why Is It Taking So Long…….? — Now I’m Done!!!

Posted by Ethos Erlanger on April 30, 2009

DONE!!! YAY!!!

I just finished the task of combining the video, music and finally the voiceover narration.  View this tutorial here.

It will be a minimum of 40 minutes to upload the video file to YouTube.  I do hope you enjoy it and send me feedback on my first ever completely original video tutorial. See all my video files on YouTube.


I just added music to the Octagon Construction Tutorial.  This required me to add a short page to the credits at the end of the tutorial.  I am working on another large construction projects and must give it the attention it is due, so videos and blogs are a lower priority.  Regarding the voiceover description for my construction tutorial, I am learning my video tutorial skills with little tiny steps and feel confident the voice will be added soon. Stay tuned.

The video assembly tools are pretty simple to use. I am using Windows Movie Maker. Doing anything for the first time is slow for many people.  I respect those that venture into uncharted waters. I am a cautious explorer except when it come to building.

Posted in Machinima, Transverse Thoughts, Tutorials, Videos on YouTube | Tagged: , , , | Leave a Comment »

Making Second Life Tutorials – Get an Alt!

Posted by Ethos Erlanger on April 17, 2009

Making Tutorials in Second Life

Lesson 1 – Get an Alt.

For those new to SL and the metaverse, an alt is a short form for the term “Alternate Avatar”.  The reason you will need one is to prevent Instant Messages (IMs) and Group Notices and Group IMs from appearing on your screen (in your screen capture) and ultimately in your tutorial video recording.

The key to using this alt is to have him or her have no friends and belong to no groups. This is the surest way to prevent IMs and group messages. You simply have no one who knows you to IM you. You could mute all your friends individually and turn off group messages for every group for your primary avatar, but that becomes a great deal of work when you want to be yourself again and RESUME communicating with these friends and groups.

Note: this is not the same as going to full screen and not showing the user interface. To create tutorials that illustrate how to use the Second Life interface or the build window (form), you cannot turn off the interface.  Hope that doublespeak makes sense.

I do not know a way to turn off local chat. To avoid some newbie walking by and asking a question, or walking into my tutorial recording session, I go to a region where I can build and then make a platform at a very high elevation of 2,000 meters. All of this is what I use to avoid having extraneous messages and avatars enter into the video.

More about tutorial  making in later posts.

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Creating an Octagon Building in Second Life

Posted by Ethos Erlanger on April 16, 2009


This video is now set to music thanks To the creative artistry of

April 16, 2009

Creating an Octagon Building in Second Life

The true geometric term for this solid object is an octagonal prism.  However, for this discussion, we will simply call it an octagon rather than split hairs over the naming of geometric forms.  This is much the same as the way we describe The Pentagon that houses the United States Department of Defense offices in Virginia. That building should be called a pentagonal prism.  We are not wrong.  We are just builders, not mathematicians.

I have searched for this answer regarding how to build such a building for myself and did not find it.  I have made hexagon (six sided) gazebos and other hexagon houses before.  I have also used this technique for making a ten-sided (decagon) building with a domed roof.  The octagon building is made with the same techniques as any multi-sides building greater than four sides.  Even a four-sided square building can be made using these steps with only one modification.  The angles used to set the walls are dependent on the number of sides.  There are more steps to creating a pitched roof for the octagon building than there are for the walls, and I will cover the process of making roofs in a follow-up tutorial. Floors for these buildings are another matter, but we will focus on the exterior walls for now.

There are scripted tools available in Second Life to position prims, but this tutorial is intended to allow you to build the octagon using only the construction methods available from Linden Labs in their standard SL viewer.

I start by planning the size of the building.  Each of the 8 wall’s length can be made from one or more prims of any size, but I tend to build with walls that have dimensions of whole numbers.  The steps involved do not rely on any measuring, so the wall size would not change the steps involved. There will be 8 walls, each having the same length. Naturally, the wall’s height does not play a factor and the thickness of the walls does not play a factor in the steps that are used to build the octagon.

Let’s choose to use a wall length of 4 meters.  Remember, any wall length will work when a builder uses this method.  Create a prim that has that dimension along either the X or Y axis.  The Z axis (height) can be any value.  Let’s use 0.5 meters for the height. Another step I take when building is to always start with the first major prim at a location on the world building grid that is a whole number.  I take this step due to the tendency of the SL calculations for prim locations and sizes to be impacted slightly by a mathematical rounding error.  This step is not required, but it is a simple standard practice which makes it easy in many cases to check your results by looking at the coordinates of the position of your prims.

1)     Create and position the first wall section.

2)     Set its length to the wall dimension that you want each of the final walls to be as measured from the outside of the building.  I use the word length to mean the measurement along the wall as you face it, such as 8 or 10 meters.  Some other builders might choose the term width for this dimension.  Sometimes the word width can be confused with thickness, and a try to avoid confusion for the reader.

3)     Now, for the purposes of construction only, make the wall thickness twice the value of what you have planned for the final wall thickness.  You may either drag the prim side to make this wall depth, or you may enter it into the object tab of the edit window.  This thickness will be reduced back to the desired wall thickness in the final step.

4)     While in edit mode, set the building grid to Local.

5)     Using the shift-drag technique, create a copy of the first wall and position it at the 50% mark based on the wall’s length.

6)     Rotate this prim 45 degrees around the vertical axis (Z).

7)     Now that this prim is set to the correct angle, move it the final 50% distance so that it is at it’s final position along it’s centerline.

8)     Create the third wall in the same way, using steps 5, 6, and 7.

9)     Repeat this process for each of the remainder of the 8 sides of the octagon.

10)  Now that all 8 prims are set in their places, the last step is to reduce their thickness by dragging the outer face of each wall in towards the center of the octagon. This is still done with the building grid set to Local.  Because we doubled the wall thickness at the beginning in step 3) we will reduce that thickness to 50% of it’s current value now.  This should bring us back to the wall thickness that we decided upon during our planning stage of this process.

I have tested these steps and used them to build a number of multi-sided objects.  If you experience difficulty with these steps, then it is entirely my difficulty in communicating their intent.

Some time soon, I hope to make a video tutorial for these steps which will surely be easier to explain in a visual form.

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