A Small Question About Displacements
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Re: A Small Question About Displacements
Posted by SDDM on Sat Nov 27th at 2:38am 2004


Just a small question about displacement maps, do they count as models? I ask because they don't appear to have any thickness, it doesn't show the actual displacement in Hammer, and they don't block vis. These are all traits of models aren't they?





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Re: A Small Question About Displacements
Posted by Fakedawg on Sat Nov 27th at 2:48pm 2004


Ya they really do resemble models. If you look at the cost/performance indicator (bind a key to +showbudget, and press that key in game to see a graphical presentation of the cost of various elements) you will see that displacements have their own bar there, so I guess the answer to your question is no ...

They are however very cheap for the engine to render - a lot cheaper than if you were to create the same kind of terrain using the old triangle method ...
[addsig]




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Re: A Small Question About Displacements
Posted by G.Ballblue on Sat Nov 27th at 5:37pm 2004


I have had some displacement objects that had... um, well, mass I suppose is the right word for it Wasn't just flat. [addsig]



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Re: A Small Question About Displacements
Posted by Fakedawg on Sat Nov 27th at 6:13pm 2004


Umm ... Care to elaborate on that G.Ballblue? Maybe even show a pic?
[addsig]




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Re: A Small Question About Displacements
Posted by G.Ballblue on Sat Nov 27th at 6:17pm 2004


*bringing one up, hang on* [addsig]



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Re: A Small Question About Displacements
Posted by G.Ballblue on Sat Nov 27th at 6:24pm 2004


fy_district0008.jpg

Not flat

[addsig]




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Re: A Small Question About Displacements
Posted by Fakedawg on Sat Nov 27th at 8:20pm 2004


Aha! Well, I do believe that when he said "they have no thickness" he meant in Hammer - were the acutal displacement doen't show up on the grid - just in the 3D view. On the grid all you see is the outline of the base brush of the displacement surface(s) ...
[addsig]




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Re: A Small Question About Displacements
Posted by G.Ballblue on Sat Nov 27th at 8:50pm 2004


... and they're also flat in game .... [addsig]



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Re: A Small Question About Displacements
Posted by omegaslayer on Sat Nov 27th at 8:51pm 2004


A displacement surface is just a height map, Yes it has no thickness (that is what a height map is. It doesnt block vis, and is not considered csg...it is considered bsp. So yo can clip to it, it wont block vis (thats why its good to put a no draw texture behind it), and it doesnt prevent leaks.

If you have played UT then you know their open maps are just one gigantic room with a height map in it (with props). This is the basic concept that we have to follow when we make displacement surfaces.

And as a little handy feature, we can make a height map in any direction (verry handy for making cliffs)

[addsig]



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Re: A Small Question About Displacements
Posted by Fakedawg on Sat Nov 27th at 9:15pm 2004


Umm ... G.Ballblue - what do you mean they are flat in game? They are only flat in game if you don't alter the height of any of the vertices ... But then there would be no point in making a face a displacement - You lost me mate ... [addsig]



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Re: A Small Question About Displacements
Posted by G.Ballblue on Sat Nov 27th at 9:26pm 2004


? quoting Fakedawg
Umm ... G.Ballblue - what do you mean they are flat in game? They are only flat in game if you don't alter the height of any of the vertices ... But then there would be no point in making a face a displacement - You lost me mate ...

Some are flat.

Some have depth.

I don't really understand why Hammer decides whats flat and what has depth, but you will come across displacements with depth, and some that are flat.

[addsig]




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Re: A Small Question About Displacements
Posted by Ultra_extreme on Mon Nov 29th at 12:35pm 2004


Hey mate, the answer is simple, your making a mistake i made for a bit, make SURE you select all sides of the brush when u create the displacement, if you only select one face then the others vanish.



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Re: A Small Question About Displacements
Posted by Captain P on Mon Nov 29th at 12:45pm 2004


No, only the sides you want to make a displacement map need to be selected. Otherwise you'll create multiple dismaps, wich isn't always necessary. For most terrain, only the top face is enough. For cliffs, a side and the top face would be a good option. It depends on what you're aiming for. [addsig]



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Re: A Small Question About Displacements
Posted by Ultra_extreme on Mon Nov 29th at 2:45pm 2004


? quoting Captain P
No, only the sides you want to make a displacement map need to be selected. Otherwise you'll create multiple dismaps, wich isn't always necessary. For most terrain, only the top face is enough. For cliffs, a side and the top face would be a good option. It depends on what you're aiming for.

?? but if you do that all other faces become invisible and cannot be textured?





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Re: A Small Question About Displacements
Posted by ReNo on Mon Nov 29th at 2:51pm 2004


Exactly, and in most circumstances you won't NEED to have the other sides of the brush visible. As Captain P said, if you were making an uneven piece of ground, why are you likely to need anything other than the top surface to be visible? If you do need them visible, you could make them displacement surfaces too, or you could make another ACTUAL brush in that location as opposed to a brush with a displacement surface on it (which stops the brush from blocking VIS, and generally acts different from a normal brush). There is no hard rule what to do here, it depends on the circumstances really. [addsig]




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