A few days ago I found a video on Twitter showing the Evans & Sutherland CT5 Flight Simulator system. It was labeled as 1981 footage and looked really amazing. The first time I saw similar 3D grahics in computer games was in the late 90s and in ealy 2000s. I wasn't suspisous because it was described as a product made for the military and I thought it's normal the technology to be more advanced.

Yesterday I showed the video to my colleagues, all of them experienced developers and computer gurus, and they said it's impossible such graphics to be achieved in the 80's. I tried to search for a proof but I found none except a short documentary on YouTube and some forum topics where people were discussing how it was achieved without mentioning anything about the exact year. I found no definitive proof that the year of creation of CT5 system was 1981. No product specifications, no publications in wellknown newspapers and not even a Wikipedia article. I'm amazed how little information is out there about something so astonishing. And this is one of the things that fuel the doubt of my colleagues.

Was Evans & Sutherland CT5 really created in 1981 or at least from the same decade?

My colleagues are with a high self esteem and it's hard to change their opinion on something. I'll appreciate any resource that proves or disproves the existance of such advanced graphics in the early 80s as well as some details how it was made.

In the link below you can see the two parts of the documentary I mentioned earlier and a short forum discussion about the CT5 and similar technologies. My colleagues don't consider it a sufficient proof.

CT5 Evans Sutherland Simulator - How did it work?


3 Answers 3


After some searching on the internet, I am fairly certain that it was made in 1981 or at least the same decade. I have found multiple sources that indicate the CT5 was made in or around the year 1981.

The first bit is in one of the promotional videos they made. At the very end there is a copyright statement. "(C) November, 1981". I would already believe this as it looks to be integrated into the video, meaning it would be quite impressive if somebody would have edited it. To me, there seems no reason to put in a false date for the copyright as, I would imagine, it invalidates the copyright statement. It can be found at 3:22 in this video: https://www.youtube.com/watch?v=7e7_GiCc-HA

I found a pdf scan from an article, written 24th of April 1982, about the CT5. It can be found here, https://www.flightglobal.com/FlightPDFArchive/1982/1982%20-%201104.PDF.

I also found a book called "Modeling and Simulation:: Linking Entertainment and Defense", which has a brief bit about the CT5. It states, "Nevertheless, the E&S CT5 (circa 1983) and the GE Compuscene 4 Computer Image generators were benchmarks by which all interactive computer graphics systems were measured for years.". This book says that it was around 1983 which does seem to support the claim of 1981, but it might have been a few years later. It can be found here, https://books.google.nl/books?id=HTkrAAAAYAAJ&pg=PA36&lpg=PA36&dq=e%26s+ct5&source=bl&ots=xka2n-9Uxx&sig=wfscYmgDGXB7AOlq00R9QtxDD60&hl=nl&sa=X&ved=0ahUKEwjustWX8t7WAhWJL1AKHT4wDhQQ6AEIQTAD#v=onepage&q=e%26s%20ct5&f=false

Then I also found a patent filed by E&S for "Computer graphics system of general surface rendering by exhaustive sampling" in 1985. It has talked about doing rendering surfaces with a z buffer. It can be found here, https://patents.justia.com/patent/4625289

Then there is another patent filled in 1982 for "Graphics display system using logic-enhanced pixel memory cells", which claims it is capable real time. It can be found here, https://www.google.com/patents/US4590465?dq=EVANS+%26amp;+SUTHERLAND&hl=en&sa=X&ved=0ahUKEwie5K-x-97WAhXKnRoKHduFAWo4ChDoAQgnMAA

These two patents show that in the 80's they already have the technology for real time graphics.

The forum discussion had a quote from a Wikipedia article which is from the following article, https://en.wikipedia.org/wiki/Framebuffer. This is more in case someone wants to know where it came from.

It does seem like the technology was there and with a big enough budget, you just needed to gather it and make it into something like the CT5. You have 3 different sources that all show that the CT5 was created around 1981, and 2 sources that show the technology was there. Yes, you can still argue about the sources, but honestly then you can argue any fact in a history textbook.

I hope that this answers your question or at least has informed you about something you might not have known.

  • 1
    $\begingroup$ While I was attending the University of Utah, I worked for Evans & Sutherland. In 1977, I got a night shift job in the electronics assembly department. By the early 80's I was a bench test technician. Gonrah's colleagues are probably assuming that the graphics were driven by a single electronics board. Uhn-uhn. The low-end CT5 was comprised of about 4 full-height 19 inch racks, each with two backplanes containing up to 32 circuit boards. A low-end CT5 would set you back a few million dollars in 80's money. The high-end had 10 full height racks and cost over 10 million. $\endgroup$ Aug 28, 2018 at 23:16

The CT5 was designed before 1981. I started working at E&S in May 1981. The CT5 was fully designed by then and 3 had been built. All 3 were still at E&S and hadn't shipped yet when I started. Two of them were on the test floor and the third was the engineering prototype that was later sold. The prototype was in the "snake room", so called because of all the black power cords hanging from the ceiling. I also remember seeing the prototype in the snake room when I made a recruiting visit to E&S in early January 1981. So, the prototype, at least, was up and running before 1981.

The first two CT5 systems were CH-46 helicopter simulators and the first one went to Cherry Point NAS. I don't think it shipped in 1981 as I remember it being there on the test floor for about a year after I joined the company. So, it probably shipped in 1982. As I recall, the two systems built after the CH-46 systems were AV8B Harrier jet simulators.


As John said, yes it was there because my first job was working on content for it. That was before 1981. The 'snake room' was about 20 feet from my office and I did many demos on that system. My job was as probably one of the first paid modelers in the world. It was a very impressive machine. E&S had all kinds of other equipment they had built over the years. Some of the smartest people I ever met worked there.


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