wall displacement tutorial

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chloesdad
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Thank you for a clear tutorial; a big help.
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Bob James
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Many thanks, SandroS :thumbup:
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gelbuilding
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Hi Sandros,

Thanks for the great tutorial.
I did what you suggested and had problems with the corners still. Im using Chief Architect and i have attached my file.

If you have time please try and see if you can get the same results as your example you have posted.
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wall test.scn.thea
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George Hadjistavrou
Thea Ready Material available http://www.gelmaterialhub.com
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SandroS
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there are several pretty major reasons why it's not working.

first off, the objects that you want to displace aren't joined at the corners. if you take your roof as an example, each plane is a separate object (you can select each one separately). this means that they will be displaced separately so there will be holes and/or overlaps where they join. to get you roof to displace as a whole, it would need to be modelled as one piece. but in this case you could get around this, for example by modelling a separate ridge tile over the joins.

other times you won't be able to do this, so you either make appropriate geometry (read the tutorial again, especially the bit done in the modelling application), or you don't use displacement but use bump or normal mapping instead. if Chief can't give you the type of geometry you need, then your only choice is to model this and other details in another app.

then there's triangulation. any surface you make in Chief is cut up into triangles when you export for rendering. if there are no holes in the surface and it's a simple rectangular form, then it will be exported as 2 triangles (which make up the rectangle). but any other shape, if you don't manually create your triangles, then the modelling app will do it for you and (when there are holes especially) it's rarely optimised. if you could see the coplanar edges of your model, you would see that there are lots of irregular sized triangles in any walls where there are openings. nigec posted a great example in your other thread (4th post). he also shows you what the geometry should look like if you want good displacement.

this is turn is linked to subdivision. your geometry is not optimised for subdivision, as detailed in the tut. that's why i need to increase displacement subdivision up to around 10 to even begin to see any displacement coming through, and then it's still all jagged and irregular. it's because your surfaces are made up of irregular shaped triangles when they should be more regular.
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gelbuilding
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Thanks Sandros,

I removed the file in displacement and all works good now. Is that possible?
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George Hadjistavrou
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SandroS
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we're talking about the same thing in different threads :crazy: :)
gelbuilding wrote:Thanks Sandros,

I removed the file in displacement and all works good now. Is that possible?
absolutely. this is the expected outcome because if you remove the texture then there will be no displacement applied ;)

i suggest you do some reading on Displacement to understand exactly what it is doing to your model.
Last edited by SandroS on Tue Aug 23, 2011 7:55 pm, edited 1 time in total.
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Frederik
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SandroS wrote:i suggest you do some reading on Displacement to understand exactly what it is doing to your model.
I agree...
Some time ago I posted some explanation for you... Did you read it...?? :?
Frederik wrote:Perhaps a good starting point will be to know the difference between displacement, bump and normal mapping... ;)

Bump mapping is a technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a texture map and applied before the illumination calculation is done...
Bump Mapping use a gray-scale image map to change the direction of surface normals. You can use this to simulate height, so that you can paint wrinkles and bumps.
50 % grey means neutral (no change is made), lighter means higher, darker means lower. Note that the position of faces is not actually changed; by rotating just the normals, lighting will change too, to give the illusion of a height difference. This has downsides too: the outline of objects isn't changed, so the trick is given away...
See Wikipedia for a more thorough explanation about Bump Mapping...

Displacement mapping uses a greyscale heightmap, like Bump Mapping, but the image is used to physically move the vertices of the mesh at render timeand allows you to add more vertices at render time which will be moved by the displacement.
This makes it much slower than Bump Mapping, as there need to be many more faces to render, but it is much more realistic...
See Wikipedia for a more thorough explanation about Displacement Mapping...

Normal Mapping is similar to Bump Mapping, but instead of the image being a greyscale heightmap, the colours define in which direction the normal should be shifted, the 3 colour channels being mapped to the 3 directions X, Y and Z. This allows more detail and control over the effect...
See Wikipedia for a more thorough explanation about Normal Mapping...

Hope the above clarifies better...!? :)
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Kim Frederik

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gelbuilding
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Yes I did read it,

Thanks Kim
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George Hadjistavrou
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jsteacy
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Great tutorial SandroS :clap:
It should be part of the mini tutorials the guys at thea created awhile ago because every newbie should see it, great stuff!
PierreKuehnhold
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Sandro, that's great information!
really helpful
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