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Author Topic: 3D Modeling - Tom Alyea’s Sniper’s Nest  (Read 3621 times)

Online James Hackerott

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3D Modeling - Tom Alyea’s Sniper’s Nest
« on: October 14, 2021, 04:58:47 AM »
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I’ve spent a great deal of time the last few months completely renovating my 3D model of the Sniper’s Nest. I’m using my recent enhancement from a WFAA news broadcast of Tom Alyea film taken earlier in the day.  By registering and stacking about 170 frames a virtual “timelapse” photo is created. This process gives a theoretical signal-to-noise ratio improvement of about 13x over a single frame for this example. Below is a comparison of a single frame versus the result of stacking with enhancement. Also is a current but evolving rendering.

Jerry would you and/or Charles model Alyea’s SN view without too much effort? I think both of you already have the basics in your models. I’m trying to simulate his film at 1:23 pm for shadow analysis and would like to compare my work with yours.



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3D Modeling - Tom Alyea’s Sniper’s Nest
« on: October 14, 2021, 04:58:47 AM »


Online Charles Collins

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #1 on: October 14, 2021, 12:30:14 PM »
I’ve spent a great deal of time the last few months completely renovating my 3D model of the Sniper’s Nest. I’m using my recent enhancement from a WFAA news broadcast of Tom Alyea film taken earlier in the day.  By registering and stacking about 170 frames a virtual “timelapse” photo is created. This process gives a theoretical signal-to-noise ratio improvement of about 13x over a single frame for this example. Below is a comparison of a single frame versus the result of stacking with enhancement. Also is a current but evolving rendering.

Jerry would you and/or Charles model Alyea’s SN view without too much effort? I think both of you already have the basics in your models. I’m trying to simulate his film at 1:23 pm for shadow analysis and would like to compare my work with yours.




Interesting study James! Sure I can see what I can do. Is there anything in particular that I need to pay attention to? Or just try to find the same view angle and set the time of day?

Online Charles Collins

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #2 on: October 14, 2021, 02:36:19 PM »
Here's my first stab at it James. I am sure that the boxes locations need some fine tuning. And sadly, the box sitting on the window sill cannot be rotated in all three of the axis. I have the z-axis as one, but have to choose between the x and y axis (if I change one, the other resets to zero). This is just one of the limitations of the software I use. The windows are generic, not very similar to the actual ones. And it appears that there is an exterior projection of the dividing post between the windows that I haven't modeled correctly. Please let me know if I can do anything that will help you further. Thanks for asking!


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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #2 on: October 14, 2021, 02:36:19 PM »


Online James Hackerott

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #3 on: October 14, 2021, 09:16:45 PM »
Here's my first stab at it James. I am sure that the boxes locations need some fine tuning. And sadly, the box sitting on the window sill cannot be rotated in all three of the axis. I have the z-axis as one, but have to choose between the x and y axis (if I change one, the other resets to zero). This is just one of the limitations of the software I use. The windows are generic, not very similar to the actual ones. And it appears that there is an exterior projection of the dividing post between the windows that I haven't modeled correctly. Please let me know if I can do anything that will help you further. Thanks for asking!


Thanks Charles! You are too fast for me. I’m wanting to pin down the time as close as possible for Alyea’s SN film of the rest boxs. Here are a few gifs and another “time-lapse” taken before Alyea’s SN.

First is a time-lapse of two detectives, I’m not sure which ones. Note the light and shadow hitting the west face of the book stack center frame.  The kneeling detective seems to hold a rifle (it looks slightly curved because it was moving during the exposures) just to the left of the History Channel logo. The standing detective is in motion during this image and is blurred as expected in the time-lapse. Anyway, that shadow pattern in helpful for timing and positioning, but in Alyea’s film of the gun rest boxes sunshine no longer hits the west face. As the animation progresses notice the development of light and shadow on the vertical brickwork of the window well at the north edge. In the Alyea rest box time-lapse that shadow pattern is just noticeable. I think this may be the best indicator of the time, but is difficult to simulate due to my modeling errors of the window parts. 


Another problem I’ve had is using the window opening of 17”, which I believe Jerry has posted in the past. The problem appears with the shadow that hits the northern corner of the window box, and is barely observable in the Alyea footage. At 17” the shadow is too large and I need at least 18-18.5” to match Alyea. Probably errors in my window construction.

Your rendering looks pretty good. As for the light/shadow hitting that book stack that upper shadow is due to the horizontal window muntin. Would you try to narrow the time interval where the shadow first hits that book stack’s west face, as well as the time the face is in total shadow? In my sims the shadow hits the top right edge a few minutes before the bottom edge.

Also the time you first see light hitting the window vertical bricks will be helpful. 

Your window box looks to be positioned pretty good. Would you increase the open window height until the box top only shows a small shadow on the northern corner?

If you would rather exchange info by email just let me know by pm.

And Thank you for your help!



Online Charles Collins

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #4 on: October 14, 2021, 09:59:13 PM »
Thanks Charles! You are too fast for me. I’m wanting to pin down the time as close as possible for Alyea’s SN film of the rest boxs. Here are a few gifs and another “time-lapse” taken before Alyea’s SN.

First is a time-lapse of two detectives, I’m not sure which ones. Note the light and shadow hitting the west face of the book stack center frame.  The kneeling detective seems to hold a rifle (it looks slightly curved because it was moving during the exposures) just to the left of the History Channel logo. The standing detective is in motion during this image and is blurred as expected in the time-lapse. Anyway, that shadow pattern in helpful for timing and positioning, but in Alyea’s film of the gun rest boxes sunshine no longer hits the west face. As the animation progresses notice the development of light and shadow on the vertical brickwork of the window well at the north edge. In the Alyea rest box time-lapse that shadow pattern is just noticeable. I think this may be the best indicator of the time, but is difficult to simulate due to my modeling errors of the window parts. 


Another problem I’ve had is using the window opening of 17”, which I believe Jerry has posted in the past. The problem appears with the shadow that hits the northern corner of the window box, and is barely observable in the Alyea footage. At 17” the shadow is too large and I need at least 18-18.5” to match Alyea. Probably errors in my window construction.

Your rendering looks pretty good. As for the light/shadow hitting that book stack that upper shadow is due to the horizontal window muntin. Would you try to narrow the time interval where the shadow first hits that book stack’s west face, as well as the time the face is in total shadow? In my sims the shadow hits the top right edge a few minutes before the bottom edge.

Also the time you first see light hitting the window vertical bricks will be helpful. 

Your window box looks to be positioned pretty good. Would you increase the open window height until the box top only shows a small shadow on the northern corner?

If you would rather exchange info by email just let me know by pm.

And Thank you for your help!

I’m very happy to help. You have helped me several times. Give me a little time to digest everything and come up with a plan. Interesting study you have going here!

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #4 on: October 14, 2021, 09:59:13 PM »


Offline Jerry Organ

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #5 on: October 14, 2021, 11:26:45 PM »
Another problem I’ve had is using the window opening of 17”, which I believe Jerry has posted in the past. The problem appears with the shadow that hits the northern corner of the window box, and is barely observable in the Alyea footage. At 17” the shadow is too large and I need at least 18-18.5” to match Alyea. Probably errors in my window construction.

I've been using an 18" opening for awhile now. And I think the window may have to go higher still. Maybe 1/2" or more, based on the Dillard photo and others.



I prefer to not give out measurements I've estimated anymore. Each modeler has to made their own subjective estimates.

Box A Box B (the carton nearest the ruler) rests on the 3/4" wooden molding used for weatherstrip.

I can't help with the shadows because SketchUp's shadow function doesn't go back to 1963. I use another moment in time claimed to mimic the sun movement in Dealey Plaza on the day of the assassination.
« Last Edit: October 15, 2021, 06:38:29 PM by Jerry Organ »

Online James Hackerott

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #6 on: October 15, 2021, 03:05:54 AM »
I've been using an 18" opening for awhile now. And I think the window may have to go higher still. Maybe 1/2" or more, based on the Dillard photo and others.



I prefer to not give out measurements I've estimated anymore. Each modeler has to made their own subjective estimates.

Box A (the carton nearest the ruler) rests on the 3/4" wooden molding used for weatherstrip.


I can't help with the shadows because SketchUp's shadow function doesn't go back to 1963. I use another moment in time claimed to mimic the sun movement in Dealey Plaza on the day of the assassination.
Thank you for your comments. I'm now sure Luke Mooney did not goof with the window when he stuck his head out to alert officials. I understand and respect your reluctance of releasing subjective measurements, no problem. I will mention that sun elevation and azimuth values for 1963 and 2021 from 12:30-13:30 are in error of less than 0.5% and basically negligible, imo. 

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #6 on: October 15, 2021, 03:05:54 AM »


Offline Rick Plant

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Re: 3D Modeling - Tom Alyea’s Sniper’s Nest
« Reply #7 on: October 18, 2021, 01:10:54 PM »
Good work James!