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Namco's Nucc Collision Model

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tormunds
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Namco's Nucc Collision Model

Post by tormunds » Fri Aug 16, 2019 8:47 pm

Hi, how's it going? I'm trying to understand how collisions work in Namco games (Jojo, Naruto Storm, etcetera), and I need some help with that. I have a file that controls the collision on a stage, but the weird thing is that it only contains vertex data. No faces at all. I assume it must be some kind of triangle strips, but I haven't been able to figure it out.

The file is divided in sections. Each section contains vertices and vertices only. No face data or anything else. Each vertex has X, Z, Y positions (all of them being float values, which means each vertex is 0xC bytes long).

File header:
0x0 to 0x4 multiplied by 0x24 -> Total size of file

Section 1 (0xC to 0x87B):
Header is in 0x4, and it's 0x8 bytes long.
0x4 to 0x8 multiplied by 0x24 -> Total size of section 1, measuring from the end of this section's header.
0x8 to 0xC -> Foot effect when characters step on this collision

Section 2 (0x884 to 0x125B):
Header is in 0x87C, and it's 0x8 bytes long.
0x87C to 0x880 multiplied by 0x24 -> Total size of section 2, measuring from the end of this section's header.
0x880 to 0x884 -> Foot effect when characters step on this collision

The rest of the file is basically the same. More sections until EOF.

Here's the sample file I used:
hit model.xfbin

Thank you in advance!

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shakotay2
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Re: Namco's Nucc Collision Model

Post by shakotay2 » Fri Aug 16, 2019 10:50 pm

tormunds wrote:
Fri Aug 16, 2019 8:47 pm
I have a file that controls the collision on a stage, but the weird thing is that it only contains vertex data. No faces at all. I assume it must be some kind of triangle strips, but I haven't been able to figure it out.
I tried auto created "standard" triangles, no strips, and worked:
.
hitmodel.png
(using hex2obj, view links in my sig)
You do not have the required permissions to view the files attached to this post.
Bigchillghost, Reverse Engineering a Game Model: viewtopic.php?f=29&t=17889
extracting simple models: viewtopic.php?f=29&t=10894
Make_H2O-ForzaHor3-jm9.zip
"You quoted the whole thing, what a mess."

tormunds
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Re: Namco's Nucc Collision Model

Post by tormunds » Fri Aug 16, 2019 11:28 pm

shakotay2 wrote:
Fri Aug 16, 2019 10:50 pm
tormunds wrote:
Fri Aug 16, 2019 8:47 pm
I have a file that controls the collision on a stage, but the weird thing is that it only contains vertex data. No faces at all. I assume it must be some kind of triangle strips, but I haven't been able to figure it out.
I tried auto created "standard" triangles, no strips, and worked:
.hitmodel.png
(using hex2obj, view links in my sig)
No way! Was it really that simple? Thank you so much!

These triangles are basically just 1/2/3, 4/5/6 and so on?

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shakotay2
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Re: Namco's Nucc Collision Model

Post by shakotay2 » Sat Aug 17, 2019 6:53 am

tormunds wrote:
Fri Aug 16, 2019 11:28 pm
These triangles are basically just 1/2/3, 4/5/6 and so on?
In principle: yes.

# autocreated linear face indices (wavefront obj notation)
f 1/1 2/2 3/3
f 4/4 5/5 6/6
f 7/7 8/8 9/9
...

but this includes texture faces (for "standard" meshes).

Since it's a collision mesh here
f 1 2 3
f 4 5 6
f 7 8 9
...

should do.
Bigchillghost, Reverse Engineering a Game Model: viewtopic.php?f=29&t=17889
extracting simple models: viewtopic.php?f=29&t=10894
Make_H2O-ForzaHor3-jm9.zip
"You quoted the whole thing, what a mess."

tormunds
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Re: Namco's Nucc Collision Model

Post by tormunds » Tue Aug 20, 2019 6:06 am

shakotay2 wrote:
Sat Aug 17, 2019 6:53 am
tormunds wrote:
Fri Aug 16, 2019 11:28 pm
These triangles are basically just 1/2/3, 4/5/6 and so on?
In principle: yes.

# autocreated linear face indices (wavefront obj notation)
f 1/1 2/2 3/3
f 4/4 5/5 6/6
f 7/7 8/8 9/9
...

but this includes texture faces (for "standard" meshes).

Since it's a collision mesh here
f 1 2 3
f 4 5 6
f 7 8 9
...

should do.
Thank you so much! That worked perfectly! :)

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