Eporting NMap from Big Mesh

[eternalfiresong]

Hello - I have what I suspect is a newbie question here... So, I have a very large poly mesh (6M) I wish to import from ZBrush (this is prior to figuring out how to convert the obj model into voxel for refinement within 3DCoat. Unfortunately, I have about 40 very high resolution models already to the retopo stage...). I import the low poly mesh, and then the big mesh on top of it fairly okay. At least it claims to have loaded. However, nothing visibly changes. And when I go to export the retopo with a normals map, I'm getting a map from the low-res reference mesh, not the high-res big mesh. Am I loading it incorrectly? I'm not sure where in the process I am going wrong, but I'm obviously missing something somewhere. Thanks for the help.

[cakeller]

Hello - I have what I suspect is a newbie question here... So, I have a very large poly mesh (6M) I wish to import from ZBrush (this is prior to figuring out how to convert the obj model into voxel for refinement within 3DCoat. Unfortunately, I have about 40 very high resolution models already to the retopo stage...). I import the low poly mesh, and then the big mesh on top of it fairly okay. At least it claims to have loaded. However, nothing visibly changes. And when I go to export the retopo with a normals map, I'm getting a map from the low-res reference mesh, not the high-res big mesh. Am I loading it incorrectly? I'm not sure where in the process I am going wrong, but I'm obviously missing something somewhere. Thanks for the help.

are you importing the big mesh as a reference mesh from the file import "big mesh" (which is for, importing those big ref meshes?

[eternalfiresong]

are you importing the big mesh as a reference mesh from the file import "big mesh" (which is for, importing those big ref meshes?

Yes what I did was take a model that was semi-refined and around 20K polygons from Maya into ZBrush (no UV map). I smoothed that lower res model, then upped the polys a great deal (as I said) and did some fine detail work at the upper level resolution. I then did some arbitrary UV map in ZBrush, exported both the lowest resolution and highest resolution models from ZBrush. I imported the low res one for 3DCoat to read, then the high res one as a "big mesh." 3D Coat will not read the large model as a regular import. And it still runs out of memory sometimes when it is imported as a 'big mesh.'

So... I'm not sure if I should have UV mapped it in Maya (that was my next thing to check). But 3DCoat acts like it is importing the big mesh, I'm just not seeing any change in how the model looks, nor the normal map export. I'm not really caring about the real time look, but I do need that normal map export to be correct...

[cakeller]

Yes what I did was take a model that was semi-refined and around 20K polygons from Maya into ZBrush (no UV map). I smoothed that lower res model, then upped the polys a great deal (as I said) and did some fine detail work at the upper level resolution. I then did some arbitrary UV map in ZBrush, exported both the lowest resolution and highest resolution models from ZBrush. I imported the low res one for 3DCoat to read, then the high res one as a "big mesh." 3D Coat will not read the large model as a regular import. And it still runs out of memory sometimes when it is imported as a 'big mesh.'

So... I'm not sure if I should have UV mapped it in Maya (that was my next thing to check). But 3DCoat acts like it is importing the big mesh, I'm just not seeing any change in how the model looks, nor the normal map export. I'm not really caring about the real time look, but I do need that normal map export to be correct...

As I understand the UVs MUST exactly match between the high and low res mesh.

If that's not easy / possible, you could import the high res mesh for per-pixel painting with NO SUBDIVISIONS and then go into the retopo room and import your 2k mesh (in the retopo menu, not file menu)

this will bring your 20k mesh in with UVs, and allow you to wrap it around the high-res mesh.

You can't do the big mesh option unless the UVs correspond 1:1 between your meshes.

In fact, I don't think you can even do it if you smooth the UV baounds because there won't be a direct relationship between UVs and points.

Let me know if that works or doesn't

[eternalfiresong]

As I understand the UVs MUST exactly match between the high and low res mesh.

I had a single model in ZBrush with multiple levels of divisions. I applied an arbitrary UV map on this single model, and exported low and high res versions. I'm not sure how else to match UV maps. Prior to doing this, I received an error message informing me that said UV maps needed to match. After the ZBrush export, that error did not appear. I guess I assumed that I had taken care of the UV problem, but perhaps not.

If that's not easy / possible, you could import the high res mesh for per-pixel painting with NO SUBDIVISIONS and then go into the retopo room and import your 2k mesh (in the retopo menu, not file menu)

this will bring your 20k mesh in with UVs, and allow you to wrap it around the high-res mesh.

You can't do the big mesh option unless the UVs correspond 1:1 between your meshes.

In fact, I don't think you can even do it if you smooth the UV baounds because there won't be a direct relationship between UVs and points.

Let me know if that works or doesn't

Thank you cakeller for your help! However, 3DCoat already doesn't like importing these high res meshes as a 'big mesh' much less anything else. I usually get a memory fault. This is understandable, seeing as these meshes are over 5 million polygons each (sometimes up to 10 million). In other words, even without subdivisions or smoothing, I could not get the large high-res mesh to import.

However, I went into ZBrush, exported a level 1 'reference mesh' and decided to do the retopo-ing on these. This way I get a mesh around the right shape. I then take it into XNormal to export out my normal maps between this new retopo model and the high-res model, as I need to get these done ASAP for a job. I'll then paint the low res retopo model and export that map from 3D Coat. It's not a great workflow, but at least it is getting my work done.

Ha, my pipeline has many kinks in it...

I appreciate the help and will continue to look into this after this particular job is done.

[cakeller]

I had a single model in ZBrush with multiple levels of divisions. I applied an arbitrary UV map on this single model, and exported low and high res versions. I'm not sure how else to match UV maps. Prior to doing this, I received an error message informing me that said UV maps needed to match. After the ZBrush export, that error did not appear. I guess I assumed that I had taken care of the UV problem, but perhaps not.

Thank you cakeller for your help! However, 3DCoat already doesn't like importing these high res meshes as a 'big mesh' much less anything else. I usually get a memory fault. This is understandable, seeing as these meshes are over 5 million polygons each (sometimes up to 10 million). In other words, even without subdivisions or smoothing, I could not get the large high-res mesh to import.

However, I went into ZBrush, exported a level 1 'reference mesh' and decided to do the retopo-ing on these. This way I get a mesh around the right shape. I then take it into XNormal to export out my normal maps between this new retopo model and the high-res model, as I need to get these done ASAP for a job. I'll then paint the low res retopo model and export that map from 3D Coat. It's not a great workflow, but at least it is getting my work done.

Ha, my pipeline has many kinks in it...

I appreciate the help and will continue to look into this after this particular job is done.

Good luck with your project. Sorry this didn't help. BTW, how much ram do you have? are you on 32 or 64 bit? if on 32 bit, do you have the windows /3g setting as recommended in the manual?

Not suggesting you mess with this right now, but when your project is over, it could help narrow down the issue.