Backface visibility

If you force Rhino to 3.3 or lower Raytraced should fall back to CRhinoDib for drawing its results to the viewport. This is communicated in the HUD by the string NoGL. Another way to force that is by set RhinoCycles.UseDrawOpenGl to false.

To be honest I don’t have high hopes for this card. You may recall our attempts to get Rhino viewports on my HD8650 working. The drawing is messed up… (viewports showing wrong and warped contents)

…you guys are way over my head, I’m just a simple designer…!!..I never rendered in Rhino, always exported to Shot…from what I’m reading, sounds like I need to upgrade to a new more powerful laptop…

Sorry John, we sort of went of the rails here… I was only mentioning to Nathan (the developer of Raytraced mode), that I’m not getting any results in Raytraced mode for my current Radeon card…and although it is somewhat related to this thread, it has nothing to do with the problem you’re seeing.

I’ll try to get things back on track here…

There are very specific reasons for why things are the way they are in V6, and if you’re interested in the details, I’d be glad to provide them here (beware, this would be a short novel :slight_smile: ).

For now, just know that older hardware has a very difficult time supporting newer features in newer versions of OpenGL that have been released after the video cards were released. With each new release of OpenGL, video card companies find it harder and harder to update drivers for older hardware, and eventually reach a point where they simply cannot implement something in the driver since the physical hardware just can’t support it…and so they stop releasing updates for specific products and/or series of GPUs. This is why I’m currently stuck with a driver from 2013 for the Radeon HD card I’m currently using…and that driver only supports OpenGL 3.3… The current OpenGL version is 4.6 …so you can already see a huge gap and loss in functionality

Since companies like AMD aren’t making new driver updates for certain models of cards, it also means they’re not fixing any bugs that may be discovered…so users are stuck with whatever the latest driver is for their specific card. Sometimes though, certain bugs can be worked around by the developers of the applications (like Rhino)… We figure out different ways to do the same thing, but do it in a way so as not to expose the known bug. However, there are times where even workarounds aren’t possible, and well, it is what it is.

Without going too far into the details…

In short… V5 uses about 1% of your video card (GPU), whereas V6 uses, on average, about 90% of your GPU at any given time…and the new Raytraced mode can use up to 100% of the GPU, 100% of the time, depending on the GPU make and model. V6 also makes extensive use of your GPUs memory… If Rhino can place something in GPU memory, it will… Meshes, Textures, Curves, Shaders (mini programs), … you name it. V6 relies so much on GPU memory now, that too little memory can actually be problematic.

It’s difficult to explain all of this in layman’s terms, and it’s difficult for users to understand hardware limitations, especially when V5 is working just fine for them… The bottom line is that V5 doesn’t push hardware limits at all, but V6 tries to push your hardware to its maximum…and sometimes, for some configurations (especially older ones) the maximum is simply not enough. We try to throttle back as best we can, but when throttling back means we eventually do what V5 does, then you’re not really getting any benefit in V6 over V5 in terms of the display and all of its new features and capabilities.

If you are able to upgrade your computer, then I highly recommend you do. I’m not going to give any specific video card recommendation…other than this:

Get a computer with as much memory as possible, using one of today’s latest and greatest video cards with as much GPU memory as possible… I would say that 4GB of video memory would be the minimum I would get given today’s standards (note: Your current video card only has 512MB). I’d also try to get one with as large of an SSD (hard disk) you can afford… You do that, and you’ll be able to experience all of what V6 has to offer, rather than battle with V6, trying to get it to work with or workaround certain hardware limitations.

In the mean time, I’m still going to keep at it here to see if I can actually get V6 working with this Radeon HD 3870.


I doubt that not having this will stop anyone from using V6, but at some point when you have time I, for one, would be very interested in reading the story - especially since the V6 display represents a pretty major jump in capabilities - of the hardware and software improvements available today over what was available for V5 and the design decisions and their reasoning for V6.

If your effort to write this runs true to form I suspect it will also be a big help to you in planning for the next bunch of improvements.

…and so here you are, just like the video card OEMs: trying to decide at what point to give up beating the dead horse and devoting your development time to more forward-looking endeavors. :slight_smile:

…Jeff and Nathan, no worries, thanks so much for the enlightening technical explanation how v6 works relative to v5 and prior builds, and explaining in a way that a non tech, like me, can understand…I was a surprised how well v4 works on this laptop, but I knew this day was coming, the tech moves on…thanks too for the clear recommendation on the kind of specs a replacement computer will need, really appreciate…happy to know you guys are out there and figuring this stuff out…!!