3D Terrain modeling question.

[Maryhill Matt]

First of all, Happy new year to you all! Hope you had a good one!

Right lads/ladettes, I have a 3D terrain model of a site which we are currently working on, I would like to add the arial photograph to it making the photo follow the 3D terrain. is there anyway of making a flat Jpeg image stamp on to a 3D terrain?

any help would be great.

Matt

Edited January 8, 2009 by Maryhill Matt

[GWS]

You could try using the jpeg to make a texture from, but I don't know if you can apply a texture to a terrain model. (You can map a texture of a photo onto a solid)

HTH,

Guy

[CipesDesign]

Very difficult, perhaps impossible to do. If it were to work, the scaling of the texture would have to be *exactly* equal to the Site Model. Also, for any close-up views the "flatness" would look wrong (without adding 3d objects, like trees, rocks, buildings, etc.). For aerial shots it might be passable.

PS: Thanks for the New Year's Wish, but could you see it in your heart to remove the rather obnoxious animated flasher??

[Maryhill Matt]

Haha that's the Flash removed, sorry for the migranes.

I will have a look into to trying some of these ideas, but please do keep them coming as It would be a good help if I could get the solved

Matt

[HoskinsArchs]

Hi there.

I am a colleague of Maryhil Matt and I am working on the same problem. We are using VW2009 Architect with RenderWorks.

With VW/RW2008 we have managed successfully to map a jpeg as a texture onto a terrain model, but only after converting it to a mesh. This reduces/negates the possibilities to adjust the terrain. Matching a jpeg accurately onto an object is a challenge but not impossible ? though the user interface could be vastly improved for this. It is also true that from groundlevel the aerial jpeg will look distorted, but for aerial views or flyover animations it is good enough (I've posted a sample image).

With our current model we have the problem that the geometry of the terrain model is too complex to convert into a 3D mesh. It seems possible to apply a jpeg onto a terrain model via a texture on the render tab - however nothing really happens when I try this.

Does anyone has any other ideas?

[michaelk]

I'm a DTM idiot - but - could you extract a surface from the DTM? You can easily apply an image texture to the extracted surface. And it would be easy to extract a new surface whenever you change the DTM.

michaelk

[panta rhei]

Textures can certainly be applied to a DTM, but as Peter says, aerials have to be exactly the right size. And they do look funny, if not ridiculous. Can't recommend.

[HoskinsArchs]

Panta rhei:

I have to disagree. It certainly depends what kind of texture you use to apply onto a terrain model.

The benefit of it is that you could for example apply a 2D road layout as an image to a 3D model and update only the jpeg if changes. Whoever has tried to work with the 3D road tool in vectorworks will aprobably agree that it is a nightmare and not suitable for larger models.

However when you are saying that 'textures can certainly be applied to a DTM' - have you done this succesfully before? I've described the process in my previous post but it doesn't seem to work. It is also not documented in the help files and as far as I can see it is just not working, at least not for complex terrain models. If you know how to apply a texture onto a DTM let me know. I'll promise to post the result and you can judge for yourself whther is looks funny or ridiculous.

Attached are the top view of the 3D terrain model (6km square) as well as a jpeg texture applied onto the top view in photoshop.

[panta rhei]

Ahh, yes, you are definitely right: there are situations, when an aerial on the topo makes sense. But it still looks ridiculous...

Anyway, I don't think that VW is the right platform. There are programs that simply place a georeferenced aerial on the terrain model.

I haven't tried large, complex DTMs & aerials ever and not even small ones in 2008 or 2009, but technically applying a texture is possible.

[CipesDesign]

You could try the "Drape Surface" command over the site model, set very fine, then try texturing the resulting nurbs surface...

[HoskinsArchs]

Thanks Peter. I tried the draping surface previously, but it made the terrain model look like a table cloth (that's also the way the tool is described in the documentation as far as I can remember). I might try to use a very fine grid - although it may well be to complex to compute if VW doesn't let me create a 3D mesh of the terrain model. thanks for your input.

[HoskinsArchs]

RE: panta rhei.

I haven't seen any of your work so our ideas of ridiculous may differ. I still believe that the function of mapping onto terrain model doesn't work in VW/RW, i.e. you can apply a texture but RW doesn't render it, wheras it does render onto a 3D solid or 3D mesh.

PS: whether I can use another platform or not is a matter of financial resources.

Edited January 9, 2009 by HoskinsArchs

[panta rhei]

Well, it's mainly vegetation and any water bodies.

No rendering? With a normal texture it certainly works.

If you happen to be a Windows-user, there is at least one free, open-source program cabable of this function and huge terrain models. If I only could remember what is is... Saw it at a University 4-5 years ago.

[islandmon]

Terrain Mapping is a fascinating subject without an easy solution.

During a lull in my work back in 2007 I began writing an algorithm

to convert the NASA 15m Radar Telemetry Data into a DTM for surface

mapping using Blender as the intermediary and dsf2text as the data converter.

It is possible with a little work and luck .. i just ran outta gas on it.