I have received some communications from people who are now working to replicate the Bluff Creek digital site model I presented in my report. This thread is specifically to discuss that digital model and help answer questions people may have as they work to replicate it in a software they use. So I will greatly appreciate if all comments not related to this focused thread be made in the new genreal thread about my report instead.

Thank you for your cooperation in this.

For anyone using Bryce, I can offer any advice on the software itself, as I have used it extensively for 12 years, and the model I made was done in it. For Lightwave, MAx, Maya, Softimage, Truespace, or others, I'll try to help, as much as i know those applications.

Bill

Please follow Bill's wishes in this thread. We will be watching.

One of the things I have observed is that some people apparently may be downloading Bryce to try it, and I saw one link for a free download. Even if purchased (it's not expensive), it's a fine program.

So for anyone who may be reasonably new to Bryce, the following illustrates how to set the Bryce Camera for either a 15mm lens or 25mm lens viewing angle, so you can test either. My datasheet notes I used the 15mm specs, as it was the only spec that worked for me to replicate the film.

Bill

Click to view attachment




tugboatwa:

Thank you for your support of the goal of keeping this thread focused on digital model information.

In a personal message, I have received some comments about the model and site measurements, and in reviewing these comments, I have identified some ambiguities that should be cleared up.

First, the process of creating a tree as a symmetrical lattice object requires a tree shaped image as the mesh displacement data source (the image essentially makes the 3D model), and when I originally did this, I was not particularly concerned with aligning the true object center with a point on the tree trunk where we may presume the men measured the trees. My intent of the time was simply to make a tree and position it.

The object data on my data sheet is the factual digital object center needed to replicate my model, but the object center data is not necessarily the coordinate position appropriate for measuring the tree, as the men did at Bluff Creek. The contribution of this person has brought this ambiguity to light, and I appreciate his contribution.

So I did a quick look into my scene file and there may be some ambiguity as to the digital object position (its centerpoint) and the location of the trunk where it may have been measured. TC2, for example, has its object center point left of it's farthest trunk section, and the tree leans slightly, so the object center is farther left than the trunk base where humans would measure it at about their height.

So a person using a CAD software and taking the tree object positions from the chart coordinates as being the exact measurement points from tree to tree, will result in measurements other than the measurements of Dahinden and Green, as noted in the model.

In a report revision, I will need to clarify the characteristics of the digital model to remove the ambiguity, and perhaps reset the Image files that determine tree shape, so the centerpoint is more proximate to the point on the tree trunk where we may assume men more likely measured it, a trunk height of about 5-6' above ground.

A second question pertained to the margin of error estimation I did. So the following explains how I made my estimate noted in the report.

The 1% margin of error, was derived from two methods. One was to compare John Green's three measurements to the discrepancy of his camera location, about 1' compared to three numbers all 100' or more. The second was to take all measurements, average them, and compare a 1' error to that averaged measurement number, which I believe was about 97 feet.

Suffice to say taking the overall margin of eror from each measurement yields a different percentage, and I was not certain what protocol averages them into a single overall model percentage.

Bill