I use rhino7 and rhino8 to export a basic box model, the format is obj, and the options are these: UseRenderMeshes = Yes VertexWelding=Welded NgonMode = None, but I open the obj file with notepad to check and find that the obj exported by rhino8 divides the six faces of the box into 6 objects, but the obj exported by rhino7 successfully merges the grid of the box into one object.
# Rhino
mtllib rhino8.mtl
g ___
o rhino8
usemtl diffuse_0_0_0_255
v -5.3726487159729004 0 8.3460140228271484
v -5.3726487159729004 5.5512294769287109 8.3460140228271484
v 1.6732470989227295 0 8.3460140228271484
v 1.6732470989227295 5.5512294769287109 8.3460140228271484
vt 0.37880834937095642 0
vt 0.19013659656047821 0
vt 0.37880834937095642 0.23986595869064331
vt 0.19013659656047821 0.23986595869064331
vn 0 0 1
vn 0 0 1
vn 0 0 1
vn 0 0 1
f 4/4/4 2/2/2 1/1/1 3/3/3
o rhino8
usemtl diffuse_0_0_0_255
v 1.6732470989227295 0 8.3460140228271484
v 1.6732470989227295 5.5512294769287109 8.3460140228271484
v 1.6732470989227295 0 -13.804097175598145
v 1.6732470989227295 5.5512294769287109 -13.804097175598145
vt 0.37880834937095642 0.24133080244064331
vt 0.19013659656047821 0.24133080244064331
vt 0.37880834937095642 0.99853515625
vt 0.19013659656047821 0.99853515625
vn 1 0 0
vn 1 0 0
vn 1 0 0
vn 1 0 0
f 8/8/8 6/6/6 5/5/5 7/7/7
o rhino8
usemtl diffuse_0_0_0_255
v 1.6732470989227295 0 -13.804097175598145
v 1.6732470989227295 5.5512294769287109 -13.804097175598145
v -5.3726487159729004 0 -13.804097175598145
v -5.3726487159729004 5.5512294769287109 -13.804097175598145
vt 0.18867175281047821 0
vt 0 0
vt 0.18867175281047821 0.23986595869064331
vt 0 0.23986595869064331
vn 0 0 -1
vn 0 0 -1
vn 0 0 -1
vn 0 0 -1
f 12/12/12 10/10/10 9/9/9 11/11/11
o rhino8
usemtl diffuse_0_0_0_255
v -5.3726487159729004 0 -13.804097175598145
v -5.3726487159729004 5.5512294769287109 -13.804097175598145
v -5.3726487159729004 0 8.3460140228271484
v -5.3726487159729004 5.5512294769287109 8.3460140228271484
vt 0.18867175281047821 0.24133080244064331
vt 0 0.24133080244064331
vt 0.18867175281047821 0.99853515625
vt 0 0.99853515625
vn -1 0 0
vn -1 0 0
vn -1 0 0
vn -1 0 0
f 16/16/16 14/14/14 13/13/13 15/15/15
o rhino8
usemtl diffuse_0_0_0_255
v -5.3726487159729004 0 8.3460140228271484
v 1.6732470989227295 0 8.3460140228271484
v -5.3726487159729004 0 -13.804097175598145
v 1.6732470989227295 0 -13.804097175598145
vt 0.86146998405456543 0
vt 0.62160402536392212 0
vt 0.86146998405456543 0.75866919755935669
vt 0.62160402536392212 0.75866919755935669
vn 0 -1 0
vn 0 -1 0
vn 0 -1 0
vn 0 -1 0
f 20/20/20 18/18/18 17/17/17 19/19/19
o rhino8
usemtl diffuse_0_0_0_255
v -5.3726487159729004 5.5512294769287109 8.3460140228271484
v -5.3726487159729004 5.5512294769287109 -13.804097175598145
v 1.6732470989227295 5.5512294769287109 8.3460140228271484
v 1.6732470989227295 5.5512294769287109 -13.804097175598145
vt 0.38027319312095642 0
vt 0.38027319312095642 0.75866919755935669
vt 0.62013918161392212 0
vt 0.62013918161392212 0.75866919755935669
vn 0 1 0
vn 0 1 0
vn 0 1 0
vn 0 1 0
f 24/24/24 22/22/22 21/21/21 23/23/23
Hi Pan - I do not see this here - can you please post the V7 and V8 files you are starting with, and the exact settings you are using on the Mesh page of the export dialogs.
@Pan_Chan hi, I saw the message on import_3dm issues tracker. I just tested with a simple box exporting that to OBJ in Rhino 8 using the same settings as you show in your screenshots. This is the box I get with Rhino 8:
Although unlikely I would disable both your own plug-in as the keyshot plug-in and see if that changes the results.
I am testing with an internal 8.11 build, I don’t know if there have been changes to OBJ export between 8.9 and 8.10, and 8.10 and 8.11 that could affect this issue. @tim do you know if there have been changes that could explain the issue @chen8 is seeing?
I can’t think of any changes in OBJ export that would cause what you’re seeing but your initial report was last November and I honestly can’t remember back that far. I will look at the changelog in the meantime and see if anything stands out.
I tried both platforms with “Use render meshes” and I’m getting the same results as Nathan. (I thought, based on the look of the dialogs that you were using Mac, but now I realize those were Nathan’s.)
What you’re describing is odd. I would understand it if the ‘o’ names were different. Or if the ‘usemtl’ names were different. They’re the same though so I don’t understand why the sides would get split up like that.
Why don’t you give me your model so I can see what’s going on in a debugger. Before saving, run ExtractRenderMesh, then I’ll be sure to have both the object, and the mesh, and I can try exporting a couple of ways.
@tim looks like polysurfaces get exported in an exploded manner. Attached an open polysurface contstructed of two separate planes joined together. The OBJ file contains two objects instead of just one.
In the meantime, if you create your box as an extrusion it will work the way that is expected. You can do this by running UseExtrusions and selecting Extrusion.
There’s a new YouTrack issue to track this. https://mcneel.myjetbrains.com/youtrack/issue/RH-83395 I have a fix done for it, just waiting for someone smarter than me to look over the changes I made before I try to merge it.
