MoI and Displacement Modelling

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 From:  Brian (BWTR)
1967.1 
This is a little test exercise today that I hope is of interest, showing, again, that more than one app is often appropriate.

Image A is a wall made in MoI which, very surprisingly, I could not give better than 450 polygons!

Image B shows that file in Carrara. It opened as 550 polys but, with the maximum acceptable 2 subdivides (again surprised!), the best I could get was 8800 polys--not good enough for displacement painting.

Image C. I took the MoI .obj save into 3D Coat and I was easily able (low setting!) to create 92,800 polys and Displacement paint as shown.

Image D shows that 3DC work taken back into Carrara and textured--including texture displacement in the displacement tag.

Brian

EDITED: 31 Dec 2008 by BWTR

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 From:  Brian (BWTR)
1967.2 In reply to 1967.1 
Just as well I don't need 3D to make a living!
A bit more Carrara fiddle withthat MoI/3DC file

Brian

EDITED: 31 Dec 2008 by BWTR

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 From:  Frenchy Pilou (PILOU)
1967.3 
Seems you have not "Weld along the egdes" at the OBJ export from Moi
And maybe Ngons gives more clean files if the 3D prog can reload it

EDITED: 15 Sep 2008 by PILOU

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 From:  Michael Gibson
1967.4 In reply to 1967.1 
Hi Brian, if you want to dice that wall up into smaller polygons when you export from MoI, try using the "Divide larger than" setting for that.

You can enter a distance value in there, and any polygons that are longer than that distance will get subdivided.

So for your example there try entering the value 2 for "Divide larger than" and then push the Update mesh button - that should then give you more polygons. If you want more, start to bring that value down to 1 or 0.5 .

When you use the slider, that adjusts the angle parameter which will cause a denser mesh to be created on curved areas. When you have all flat planes in your object like you do in that case, the angle parameter will not really have an effect, the only thing that it will adjust in your model there is the density of that circular hole that is cut out.

- Michael
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 From:  Brian (BWTR)
1967.5 In reply to 1967.4 
Pilou
I think most of my rendering apps don't like n-gons?

Michael.
Thanks for that info. Another bit of learning.
I was very surpised, compared to normal MoI obj efforts, at that result

Brian
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 From:  WillBellJr
1967.6 
I like the last render, Brian, really looks like a rocky surface with the texturing.

I have to get the hang of 3D Coat. I like the topology tools but similar with ZBrush, being that most of my work is mechanical / hard body, I'm not sure how much use I can get out of 3DC?...

-Will
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 From:  Brian (BWTR)
1967.7 In reply to 1967.6 
Thanks Will
The thing is that, with that clue for increasing the poly numbers that Michael gave I was able to do quite a good enough job just with the Carrara displacement painting. (Avoiding the need for 3 apps!)

Bythe time the 3dCoat version3 is fully implemented (soon), it, with MoI and Carrara, will be a great combination for just about anything.

Brian

ps The attached shows the revised poly set up from Michaels settings advice. Compare with Image A in the first post.

EDITED: 31 Dec 2008 by BWTR

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 From:  BurrMan
1967.8 In reply to 1967.7 
Nice work Brian!
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 From:  Kurt (KURTF)
1967.9 
Even for Hard Body work a paint program like 3D Coat is useful. Need a spot of rust? A dented fender?

These things are tough to do in MoI, but for 3D Coat it's a piece of cake.
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 From:  WillBellJr
1967.10 In reply to 1967.9 
Yes, I can appreciate the painting aspect but when you have a low poly model targeted for a game and you have no other choice but to blow up the poly count upon import it sorta makes the package unusable for ya.

Granted for normal mapping, it's not a problem at all as long as I make sure not to destroy the original low poly version...

-Will
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 From:  keith1961 (KEITH)
1967.11 In reply to 1967.10 
Hi all
A while back I tried importing models into 3d coat and it smoothed them all, which want very helpful as they were intended to have angles. But that's beside the point really.

The main reason for my post is that I'm a bit confused by the polygon issue. As far as I understand things less polygons is better because it uses less memory. Is there any advantage in (for want of a better example) displacement painting a wall? I've only just worked out how to UV map things properly so displacement mapping seems a bit of an advanced area at the moment and I'm wondering how and why I should use it.
Keith
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 From:  jbshorty
1967.12 In reply to 1967.11 
Hi Keith. There is no hard rule for when you should use displacement or when you can get away with just using bump/normal mapping. If your wall is made of large stones, you may want to use geometric displacement or else the stones won't look real at the wall perimeter. But if you sculpted details on the wall (paint blobs, picture frames, cracks, electrical outlets, etc) then you're probably OK to use normal/bump mapping as it will look nearly identical to the displaced surface but will render A LOT faster. The only time it would be a problem is if you rendered the wall from a glancing angle. Those details will then appear to be increasingly flat (as they are in fact painted on the wall). In situation like that, you need to use geometric displacement...

jonah

PS - 3DCoat now has an option to import the model without smoothing it. It was added for people working with CAD models...
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 From:  Michael Gibson
1967.13 In reply to 1967.11 
Hi Keith,

> As far as I understand things less polygons is better
> because it uses less memory.

That's usually the case if you want to render the object with its current shape.

But if you want to modify the shape to do stuff like add craters and lumps in it, stuff like that then in that case it can be useful to use a much more dense mesh so that there are enough points in the middle of a shape to be pushed around.

In cases like that where you want to edit the kind of inner pieces of an object that is when you might need to make more polygons to make that possible.


Another example is animation - if you want to animate an object to do something like make if flex and bend, it will probably need to be made up of a larger number of points more evenly distributed throughout the object.


There are a lot of different kinds of things you can do with a model, so there isn't only just one single rule to follow in all cases - for different tasks you may need to create polygons in different ways.

Sort of the default way is more oriented towards just rendering the object directly so by default it is usually focused on making the lower polygon count style.

- Michael
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 From:  BurrMan
1967.14 In reply to 1967.12 
As far as the polygon count, It depends on its use and inteded result. Yeah spending $1 to by a car sounds like and sometimes is a good Idea, Sometimes you want to spend $300,000 to get the McLaren F1! Just depends on what you WILL do with it.

[EDIT]
Once again Michael beats my post so I seem redundent....Please refer to the post just previous to this one.
Burr
[edit]
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 From:  keith1961 (KEITH)
1967.15 
burrman and all
Your points are all well made and informative. Thanks a lot. I'm learning fast.
Keith
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