animal??

Post JPatch model files.

animal??

Postby miyoken » Thu Dec 30, 2004 5:27 pm

Five point patch is nice.
Feel free to modify to dog ,cat,bear,rabbit,etc... :lol: :lol:
Licence:LGPL

Image

http://miyoken5.hp.infoseek.co.jp/my_chara2.jpt
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Postby Guest » Thu Dec 30, 2004 10:43 pm

Hello Miyoken,

I have been watching your work for some time now. I really like this new animal of yours - very impressive minimal modeling style. I do most of my modeling in Hamapatah and sPatch (a search on Hamapatch is what brought you to my interest very long ago). I see that you use the 5pt patch often now that it is available in Jpatch. I really need to start using this modeling program much more for just that reason (the 5pt patch). I am curious how the 5pt patch exports to rib (Renderman). I render almost all of my animation with a Renderman compilant renderer (BMRT typically). Anyway ... nice model!

Robert
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Postby rjh » Thu Dec 30, 2004 10:45 pm

I thought that I was logged on ... the above post is from me.
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Postby sascha » Sun Jan 02, 2005 3:32 pm

Hello Miyoken,

This is a very nice model indeed!

It took me quite a long time to figure it out for myself, so if you allow me a suggestion:
Always try to use regular four-sided patches. If the topology of the model does not allow this, try to solve it with hooks. If a hook doesn't work, use five-point patches. If that doesn't work either, use three-point patches.

I've replaced some of the five-point patches in your model with regular foursided ones, and some with hooks. The use of five-point patches e.g. around the eyes and where the arms and legs connect to the torso is ok - these were the regions that always caused problems in sPatch and hamaPatch...
http://www.jpatch.com/temp/my_chara3.jpt


Hello RJH, nice to see you again!
Renderman supports regular (four sided) bicubic patches. JPatch splits five sided patches internally into five four-sided ones. Unforuntely I have not yet found a way to do this without causing creases (where the five patches connect) - The creases are almost invisible, but you can notice them on reflective surfaces (or on surfaces with bright specular highlights).
I introduced a new subdivision scheme (similar to the one used in Animation:Master) to solve this problem (for JPatch 0.4), but as these "Hash Patches" are not supported "directly" by any renderer, JPatch needs to do the tesselation and can only export a triangle mesh to the renderer. The drawback is that you loose the "adaptive" subdivision REYES renderer provides (e.g. Aqsis) - I don't know how BMRT works though, perhaps it makes no difference there.

I'll continue trying to solve the problems with the bezier-patches - additionally I'll add support for Catmull Clark Subdivision Surfaces in a future version.
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Postby rjh » Sun Jan 02, 2005 5:27 pm

Hello Sascha

Thank you for your interest to solve this ... for that matter, thanks for starting Jpatch! It's a great progran as is, and once the animation is added (in ver 0.4?) it may become my main work horse. If you would like to see some animation I have done using this technology, have a look at the following link:

http://www.smartcomix.com/projects/prj_index.html

I made all the keys in Hamapatch / sPatch and created morphs between them with a program by Brian Black called "Ribtween". It works great.

As far as Miyoken's model goes, it exported the 5pt patched ok with the creasing you mentioned. Thanks again for working on the 5pt patch export for rib. I also have some suggestions for the rib export format that I will cover later. I am moving (slowly) to Aqusis & 3Delight. Renderman is what I know best, but I do see promise in the native renderer inyo that you are developing with dcuny. Great ton hear from you.

Robert
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Postby Guest » Mon Jan 03, 2005 6:31 pm

Hello Robert,

have been watching your work for some time now. I really like this new animal of yours - very impressive minimal modeling style.


Thank you.
I began to make this model from the head of sheep's model(General discussion->IRTC entry)

I think that the method of doing of the start modeling roughly, increasing the number of splines by "Tab & Insert", and making to details is good.

I really need to start using this modeling program much more for just that reason (the 5pt patch).


Yes.It's time for Jpatch :lol:



Hello sascha.

Your suggestion is:

<priority of patch modeling>
1.--regular four-sided patches
2.--hooks
3.--five-point patches.
4.--three-point patches.

I understood.
Did I use five-point patches too much?
The new feature comes to want to use it fully.

I've replaced some of the five-point patches in your model with regular foursided ones, and some with hooks. The use of five-point patches e.g. around the eyes and where the arms and legs connect to the torso is ok - these were the regions that always caused problems in sPatch and hamaPatch...
http://www.jpatch.com/temp/my_chara3.jpt


Thank you for the correction & the modeling course. :lol: :lol:

I'm looking forward to the bone system.
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Postby miyoken » Mon Jan 03, 2005 6:35 pm

The above post is from me. :)
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Postby rjh » Mon Jan 03, 2005 10:52 pm

Hello Miyoken / Sascha,

Just an FYI - Hamapatch just updated to ver 3 preview 1.03 with 5pt patches (seems very coincidental). His 5pt patches do not export to rib though. It also implements SDS - still trying to figure that out through the interface though. I'll post some models soon.

Robert
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Postby sascha » Mon Jan 03, 2005 10:57 pm

Hello Miyoken,

<priority of patch modeling>
1.--regular four-sided patches
2.--hooks
3.--five-point patches.
4.--three-point patches.


Yes, that's what I believe works best to avoid creases.
Hooks are of use where regions with high details (many patches, e.g. on a face) need to be connected to regions with low detail (only few patches, e.g. on the backside of a head).
5- and 3- point patches are needed to create arbitrary topology meshes, e.g. to connect an arm to the shoulder, etc.
[PS: There are some topologies that require six-sided patches... I think of implementing them]

The next version of JPatch will use Hash-Patches internally - these will render without creases (in the realtime z-buffer renderer), so if you spot cracks or creases then, there is a problem with the mesh.

Did I use five-point patches too much?

It wasn't my intention to criticise your model (which I think is very well done). I just noticed that you used 5-point patches where hooks would have been a better choice. In short, whenever you have topologies like this...
Image
...use a hook (at the point with the red marker), don't make the patch on the left side a five-point patch.

The new feature comes to want to use it fully

Hooks are a "new" feature as well :D (when compared to hamaPatch).

Btw, you once wrote that hamaPatch had a "symmetry" or "mirror" mode, but I couldn't find it. Can you tell me how to activate it?
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Postby miyoken » Tue Jan 04, 2005 3:23 pm

Hello Robert,

Just an FYI - Hamapatch just updated to ver 3 preview 1.03 with 5pt patches (seems very coincidental).


Yes, but it doesn't support hooks... :(

It also implements SDS


The samples (5point_patch.hmp ,mirror.hmp ,subdivision_surface.hmp) are included now . :)

Hello Sascha,
Hooks are a "new" feature as well (when compared to hamaPatch).


I did not understand well how five-point patches and hooks should have been used properly.

Btw, you once wrote that hamaPatch had a "symmetry" or "mirror" mode, but I couldn't find it. Can you tell me how to activate it?


Do you look for "freeze"?
Open the mirror.hmp.
You can see the mirroed object.
"Model menu->Freeze" is same as auto mirror of JPatch.
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Postby sascha » Fri Jan 14, 2005 7:37 pm

Hello Miyoken, sorry for not answering earlier (I was very busy preparing the IRTC animation).
I did not understand well how five-point patches and hooks should have been used properly.

Take a look at that cool dragon-head model pndragon posted to the WIP forum. He ran into the same 5-point-patch/hook problem. I've uploaded a picture showing how to resolve this kind of problems, hopefully making a bit more clear.
I'm going to change JPatch to reject such "degenerate" patches, to make it easier to spot them...
This will slightly break sPatch/hamaPatch compatibility, but also forces users to use JPatch's features (hooks and 5-point-patches) to "correct" the sPatch models...
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Postby miyoken » Sun Jan 16, 2005 3:18 pm

Hello Sascha.
Please don't mind.
.
I've uploaded a picture showing how to resolve this kind of problems, hopefully making a bit more clear.


Thank you. :) :)

I'm going to change JPatch to reject such "degenerate" patches, to make it easier to spot them...


It's nice idea.
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