changing geometry

[elfufu]

question, what if i have a very detailed model that i have zbrushed for hours and say the art deprartment wants me to completely redo the arm in a way that i would need to add geometry to the base level 0. or say add a new arm all together. how can this be done?

also how can i apply the displacement map i just created to a low resolution model inside of zbrush..can i still divide it at that point? thanks in advanced.

[Game Master 770]

A1- if you made you model out of zspheres, adding an arm is a non-issue. Otherwise, you would need to do it outside of Zbrush, since you can not create new geometry to a model.

A2- displacement mapping works in zbrush, and most other apps, by applying multiple sub-d levels. The displacement map, will adjust the higher sub-d levels. IOW, you can't see the results at the low res. this goes for any app. At some point the geometry needs to be divided to show the displacement. either the app will do it, or your renderer.

[elfufu]

game master you are misunderstanding my question.

[aminuts]

he is not misunderstanding your question.....his answer to the first question is quite simple and your answer if your model is still in zspheres like he stated. and if its not he also answers your second question....you cannot add geometry to your model.

as for your second question....applying your displacement to a low poly object... depending on how you used zbrush to create it yeah you can use it on your low poly model or the lower poly one you created in z2.

as for subdividing that model....I am not sure as it never occurred to me to try it.... I reckon you could subd it if you deleted all higher and lower levels and started over but I cannot be sure the displacement would still be effective...but seems to me it would or at least should be.

[Bonecradle]

This is a good question, and if I can paraphrase I think the real issue/question is "can I add geometry to an already detailed model without losing all of the detail work I have done".

I think the simple answer is no, though I haven't had much of a chance to play with Z2 so I am happy to be shown wrong.

I do know, however, that you can't do this by altering the zsphere model - doing this would wipe all previous geometry editing.

You could try generating successive interior edge loops from one poly and manipulating that into the desired new geometry - or does creating edge loops on lower subd levels also wipe editing? - one to experiment with.

One way around this would be to find the easiest way to reapply the detailing. If all else fails you can save out the old highest level model, cut it into bits and use them in PM to displace the new, lower level geometry. I'm sure it would need touching up though.

[skycastle]

What I do in this case is to use maps to
displace verts on the new mesh. This works if the UVs ( on the new mesh ) are about the same.

1. Create maps for your current geo.

2. Import you new modified geo.

3. Subdivide the mesh a few times.

4. Use the old maps to add the old detail to the new mesh.

5. Then unsubdivide the mesh back to the lowRes.

There are other ways to solve this but you
would need to write a plugin or two. Plus
Zbrush would need be able to output float
maps.

[reboren]

Skycastle, how similar do the UV's have to be. How much time do you spend lining up the UV's of the two models?

Thanks.

[aminuts]

cool...I am glad you replied skycastle. I was thinking along similar lines that that would have to be the way to do it but hadn't gotten so far yet to try it.....I am glad to know it has possibilities!

one question tho.....did you try this with the low poly version or with a zbrush created lower poly version (sorry I forget what zbrush calls it.....when you make a cage from the high rez model)? Or a reworked low poly obj from another app?