- First, using Blender Export USD all glass came in invisible, even if I selected them in the Stage tree (ie no mesh outline highlight). I had to go to the Materials folder in the Stage and use Select Bound objects and then drag the glass material from the Materials tab onto that selection (which was good UX). However, now that I’m linking that model into a new scene, none of the glass is transparent. Why is that? The mesh is a solid with proper thickness.
- One similar note to the above, as you can see in the screenshot, the white plastic (from the Materials tab, so I presume it’s by Nvidia) in the details panel has a yellow thumbnail. I have no idea why, since I haven’t done anything to it beyond dragging it onto some objects.
- When I dragged the Ocean_Small from Nvidia into the stage (actually also when I did the same for the ferry) I got some message about unit mismatch. I have no idea why since I just created a new file, the Ocean_Small is by Nvidia and the model was exported using Nvidia’s version of Blender. Everything should be in the proper units. However, since no units are written in the details panel, I actually don’t know how large my model is.
- The Ocean_Small in my scene is white. I don’t know why. Also, is there no easier way to add the ocean than navigating to the extscache folder? Why isn’t it an NVIDIA Assets or even Environment? (Also, several black materials on my model is now white, I see… I don’t know what’s going on.)
- Maybe it has to do with the unit mistmatch, but the Area lights from the Export USD in Blender have an intensity value of close to 300 000, yet they light up very little! Again, no units exposed in the UI so what is that? Candela? Lux? Doesn’t seem like either seeing how weak they are.
- I moved one of the lights down a bit to see if it was because they had to shine through a panel of Frosted Glass (using the Nvidia Material which doesn’t look frosted at all, by the way), and now I can’t undo to move it back up to the original position…
Right now, I hit a dead end here. I don’t know how to continue because things still feel glitchy and not for a designer like me, but rather developers.
@EDRobert whilst i am not a Blender user and cannot address all of your concerns at once, i’ll start with the one that i am more familiar with:
- When I dragged the Ocean_Small from Nvidia into the stage (actually also when I did the same for the ferry) I got some message about unit mismatch. I have no idea why since I just created a new file, the Ocean_Small is by Nvidia and the model was exported using Nvidia’s version of Blender. Everything should be in the proper units. However, since no units are written in the details panel, I actually don’t know how large my model is.
i believe the error you saw was from the “metric assembler” extension, which is enabled by default in Composer. you can read more about it in the doc and a short video on what’s happening behind the scenes and how you can tell what unit the authoring USD file uses. and the benefit of the extension is it automatically changes the scale for you, so you aren’t in any problem whatsoever.
in short, i wouldn’t jump to the conclusion that the compiled Blender version from Nvidia uses consistent unit system as every OV apps across the board and you will still need to pay attention to the unit during export. feel free to dig into the general export setting’s doc.
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I don’t understand how Nvidia can claim to have digital twin support and not have better UX around that. I bet the Omniverse applications from Bentley and Siemens aren’t ambivalent about it.
Anything coming from CAD can’t have a single doubt about what size it actually is and it’s still super unclear in Omniverse!
Also, I think I saw scale 100 on some objects… actually, the .usd which was exported from Blender has scale 1, but when dragged and dropped into a new scene it gets scale 100… Omniverse needs to sort this out, I shouldn’t even have to think about it. If this is a shortcoming of USD, it needs to be handled and made invisible. There’s nobody importing real world scale objects who ever wants any doubt about what they’re importing! It’s like the first thing on the checklist.
EDIT: Also, I don’t see the bounds of an entire tree, which would be very useful, but even when I try to look at a single object, the values presented to me in the UI aren’t even human readable, let alone again lacking any sort of units…
EDIT: Ok, so you’re supposed to use the Measurement tool/panel which is neat. There’s some UX issues with that too, because I don’t know how to use the Constrain option, which I assume is to limit the measurement to a certain axis, which would be nice. I still think the above feedback is valid, though!
Further, here’s how you name and save a section:
While the Measurement has an entirely different UX (I think you right-click to save and can’t name it):
Plus, in the Stage tree, they both just look like Xforms unless you read their names. No special symbols or anything to visually distinguish them.
Just noticed that whenever I click on anything in my new stage where I dragged the previous USD into I get a warning like this:
