An Updated look at LoD

As BIM authors become more adept it quickly becomes apparent that a more hybrid understanding of 3D graphics is required.  This new level of modeling takes the technical drafter down the road closer toward a visualization or animator role.  Therefore a more specific description of Level of Detail/Development is required.  (Each RPF or BIM Implementation needs to have a section defining LoD as it’s specifics mean different things to different people.)

It it important to note that Level of Detail and Level of Development are different things… Level of Development outlines what a model is authorized to be used for while Level of Detail describes the model’s graphical properties and goes together with Level of Appearance Quality (LoAQ).

Level of Detail in General

LoD1: Buildings are represented by their footprint or the roof outline with a constant height value.  Inclusion of some density data or distances are possible.

LoD2: Buildings are represented by massing models.

LoD3: Buildings are represented by geometrically simplified exterior shell.  Analysis of the materials is possible leading to an estimated ‘R’ value of the wall assembly & energy conservation performance.

LoD4: Buildings are represented by geometrically exact exterior shells.

LoD5: Building interiors are included.

Geometric Level of Detail (GLoD)

GLoD1: Buildings are represented as 2D surfaces inserted into 3D space.

GLoD2: Buildings are represented as simple 3D geometry.

GLoD3: Buildings elements that are 15cm and larger are included.

GLoD4: Buildings elements that are 5cm and larger are included.

GLoD5: Buildings elements that are 1cm and larger are included.

Level of Appearance Quality (LoAQ)

LoAQ0: No minimum appearance quality is specified.

LoAQ2: Buildings are represented as “shaded with edges” and indicates true colour.  Includes shadows

LoAQ3: Building on the requirements of LoAQ2 but is expanded to include material mapping.

LoAQ4: Building on the requirements of LoAQ3 but is expanded to include full texture mapping (bump maps, transparency, luminance, reflectance…) to produce a photo real environment.

Architectural Modeling

I loved this tutorial on the area, so I don’t lose it for myself I’m posting it here – THIS IS NOT MY WORK.  it is from Juan Siquier

INTRODUCTION

In this tutorial I will go through my usual workflow with simple steps (trying to make it as simple as possible), to build a scene from preparation phase of the project (Pre-Pro) to the final render. As usual, I’m using 3D Studio Max for the modeling, mapping and lighting, and Photoshop/Bodypaint for texturing-based off the great 3D Total collection of textures.
A good habit from the start is to create a special folder for the project, another subfolder for the textures and another for the references. Another advice (I always do it) is to print one of the references so you can look at it, whenever you go to bed or a bathroom break – in this print I usually write some notes and ideas to help me reach the final image.

I start with the modeling by extruding the floor of the building, then I make cuts on the geometry with the “slice plane” tool or also the “cut” tool, and then I extrude in negative to make the windows. Each time I finish the modeling of one of the elements, I also finish the UV mapping. I don’t like to accumulate the UV mapping for the end. A few paragraphs below, I will explain briefly my technique for mapping.
In this kind of symmetrical building, it’s very useful to apply the “symmetry” modifier because this way, we can save a lot of time and work since this guarantees the perfect positioning of windows on both sides.
If the composition of the reference picture satisfies me, I usually lay the 3D model over the picture as perfectly as possible – this way I can fix proportion issues. Using the hotkey “Alt X”, I can make the object transparent to make the overlaying process easier.
For the antennas and cables I usually model it with renderable splines, making sure that I’ve activated the automatic mapping. I also watch my poly count, as I know from experience that a cable of 4 spans is enough if it’s going to be seen from a medium/far distance.
The trees at the bottom of the picture were made using Onix Tree Pro. Only the visible parts were modeled… in other words, they are incomplete trees.

For some reason I found it more simple to deform the bird neck with some bones, and a skin modifier. With this approach, I could move the bones in an interactive way to decide the final pose of the animal (always use the rendering camera, so it has more strength in the composition).

The mapping is without a doubt the heaviest and most boring process when it comes to creating the scene. It is a necessary, but not too creative process. Also the UV maps are not something spectacular to show around saying “Hey check out my cool UV map”. But in the long run, uvmapping is more like a puzzle game (it has its charm). To describe briefly my mapping process, you just have a few simple rules:
1 – You should not have overlapping UVs EVER.
2 – The checker map we put on the object has to represent perfect even squares.
3 – The objects in the UVeditor should have the same proportion as the ones in the scene.
4 – Make sure the orientation of the object is correct in the UVmap editor.
5 – It is convenient to optimize the space inside the map.
A good way to begin the mapping, is using planar maps to unfold the object and then stitch the individual pieces together, also you could equally stitch the pieces from automatic mapping. I’ve assigned the hotkey”S” for “stitch”, where I can select an edge, and hit “S” and stitch pieces together really fast. Always remember that if you put a lot of effort into the UVmapping, it will be less likely to have problems ahead once we’ve painted the textures in Photoshop.
Once I have all geometry modeled and mapped, I bake the Mental Ray ambient oclussion map. Usually I end up using that map as a dirt map. This map is very very important because I use it as a base to fake the GI, reflection masks, specularity masks and transparencey masks, (when it comes to crystals and windows). The aforementioned “baking” can be done with the “render to texture” in Max7, which is finally compatible with Mental Ray
Ok! Let’s think for a moment that we don’t want or we don’t know how to bake the ambient oclussion map (maybe you don’t have Max7) what we can do is use it on the diffuse level slot of an ONB shader (making the roughness 0)
We can combine the layers in Photoshop – underneath color > then the baked AO > in “multiply” mode and in top > “screen” mode the capture of the UVmapping which we can obtain thanks to the free plugin Texporter.

The next task is to include the textures that I have chosen from the 3DTotal collection, in the mentioned layer of color, make them overlay with UVmap captured from Texporter. Normally I also use photographic maps in grayscale which you can find in TotalTextures Volume 5. Include these layers on a top layer so you can multiply them. Naturally you have to make a lot of touch ups with the Photoshop brushes by hand, so you can paint non-mathematic dirt, cracks, and the like. I also highly recommend a graphic tablet – I use a Wacom Intuous 2 A5.

It is very tough to make the textures overlay perfectly with the model if you don’t have good continuity on the UVs. What I mean by this is that if the UVs do not have seams, you could always use Bodypaint so you can paint directly into your model or use the clone stamp as well. I usually bring the model to Bodypaint to make the final touches adding dirt in those places where the math calculation of AO does not happen.. for example, the oxide rake that leaves the rain under iron elements.

To light the scene I decided to use a target spot light very far away from the models with area shadows, using a yellowish-orangish color. I activate the ambient lighting on Vray with a little bit of blue color, and as well, I activated the GI with some predefined values (I think “High” preset) on the irradiance map.
Usually, I model the shadow casters with the help of the “light” viewport (Shift+$) so the shadows are projected exactly in the desired place.

CONCLUSION

Finally I start the render at 3000 px resolution and adjust little details in Photoshop like levels, and a couple of brush strokes in the sky as a “final touch”. Generally I condition all the work so as a result, it’s closer to an illustration where the focus is the beauty of the form and color instead of an accurate representation of the building.
All the textures of this image were taken from the huge colection of total textures of 3D Total – the color maps, the bricks, wood and concrete as well as the dirt maps.
I hope that this has been useful in helping you to make old buildings. I find it really enjoyable so I hope that you’ve enjoyed it too.

3D Scene Assets

The intent of rendering within Revit has always been for design validation as opposed to those emotional marketing type of images.  That being said Revit does have the ability to produce some pretty impressive visualization images.  Design validation images while they can be of an impressive quality tend to be lacking a sense of being “lived in”, the problem is that all of the little extras like dinner plates, fruit bowls, pictures, magazines… all increase the computing power required to process the scene and this is where Revit has a problem.  It is after all a little much to expect that your BIM solution complete with it’s data rich building components also be able to add in all those extra high poly models without slowing down the software.  So for a design intent visualization image these little extras are better left out and as a result the images tend to have a sterile feel.

This is where 3D Max comes in.  Revit exports to the FBX format which is intended to be imported into Max and will maintain all the material settings from Revit so all that is required is the addition of all the little extras.  (Unconfirmed rumours are that Max 2013 will open .RVT files directly.)

So your looking for scene assets to enhance your visualizations, of course we all want them for free, free is the right price!  I’ll list a number of sites I’ve used in the past to gather those little extras.

Just a word of warning the old saying “you get what you pay for” is still true in the world of BIM.  Also be sure you know where you can use your newly acquired assets, most publishers will have something like the following:

1. This 3D model is provided “as is”, entirely at your own risk.
2. We don’t accept any claims regarding quality of this model or any standards conformity.
3. This model may be used in any commercial way only if it is a part of artwork or project. 4. Single reselling or redistribution of this model is prohibited.
5. This model may (or may not – really watch out for this one) be freely modified or elaborated.

The basic ways of use are 3D Visualisation, Interior Design, Architectural Visualisation, Landscape Design, 3D Animation and 3D Art.

TurboSquid TurboSquid Free Assets DLegend
3D Extras Archive 3D 3D Model Free
3DM3 Exchange 3D Wirecase
Mr.Furniture Top 3D Models Archibase
ShareCG 3D Allusions 3D Auto Club
Cadalyst

These last few links are some extra’s you might be interested in as well:

3D Total (Free texture resource)

The Blueprints

Onno van Braam

Using Revit for Structural Fabrication Drawings

One of the things I found a little tricky with Revit is controlling the visibility of parts when doing a fabrication set of drawings, today I had a little breakthrough though, it’s simple really but it just eluded me.  The key is naming your inplace families correctly.  When I do a fabrication element I prefer to use inplace models as I find them easier to control to a fabrication level of accuracy (and it makes it harder for someone else to mess up on me!)  I’ll create an inplace family of one extrusion only as I want to be able to isolate individuals & like everything in Revit proper naming is key.

First create an inplace family, choose an appropriate category & name it (fig.1).  In this case I’m doing a canopy frame so I chose a generic model and called it canopy brace 1.  Model the element.  When copied the number will automatically increase.  Finish the inplace model and go to the project browser & rename the type to be a part number (fig.2).  I created a material take-off just to help me identify the individual parts, but it’s not necessary I just find it a good way to keep my parts organized.  By creating a unique material for the fabricated elements I can add a material comment and once that is done it is a simple matter of applying a filter to isolate them in the schedule.

Using a visibility graphics filter it is now an easy matter to control a view by a specific part name (fig.3).

01  fig.1

02  fig. 2

03  fig. 3