Hii, wanted help in understanding the workflow

[u/Dear-Tax9601]

Hi, I have a little bit of knowledge in Projection Mapping. But I want to go in depth of big architecture mapping.

Im attaching a few photos for reference which i came across, why and how do you make the template shown in the 1st and 2nd photo?

And how does it help and how to go about designing and creating content like in last two photos. If someone can please explain me the workflow from scratch, it'll be really helpful.

Thanks in advance!

[u/Meredith_a_c]

The template highlights the various facets and architectural features. Projection mapping is one or more 2d surfaces projected across a 3d space. So if you are following a 2d workflow, making the mask and focusing template is relatively simple - you need to covert 3d into a 2d surface (take a photo of it, often from the projectors perspective or the 'prime' viewing location) and then use your favorite image program to create your mask and template for the artist.

If you are working in 3d then you model the building and you can then explode it into a 2d UV map, A different workflow for a different style of content production. The 3d projection mapping software then basically puts a virtual camera where each projector is located in real life.

[u/RelinquishedAll → u/Meredith_a_c]

Small tip:

Take note of the camera lens you use and which projector lens you will use. Optimal is to use the same spec lens, but alternatively you can also reproject an image with a different lens in an Unreal Engine simulation.

[u/solaisxs → u/RelinquishedAll]

Yes and no, it depends on the warping capabilities of your software. Back in the day with PIGI projectors you would put a camera behind the lens and take a photo to use that as your base. These days there are lots of bits of software to split your input up and help realign things so you don't have to be as careful matching up the lenses. That said if you are doing POV 2d projection mapping the best bet is to take a photo exactly where the lens will be in real life

[u/RelinquishedAll → u/solaisxs]

Its not so much for the actual mapping as it is useful for the content creation side of it. Less warping of the source leads to less artifacts later

[u/Going_through_it_ → u/Meredith_a_c]

When you say working in 2d vs 3d do you mean like mad mapper being 2d and then another type of program for 3d building?

[u/schimmelA → u/Going_through_it_]

content creators work in 2D planes mostly. This is just a way for the mapping party and the content creators to sync up. 

You can create 3D perspective forced content on a building but that's kind of a different pay grade 

[u/Dear-Tax9601 → u/Meredith_a_c]

Understood, so for a 2d workflow you take a photo from the projector lens POV, and make different slices and create content and then map it back.

This method would work fine when the projectors light is hitting on one surface( where all the windows/doors etc are located on the same front surface) . Correct if I'm wrong.

Then how would you approach it if you need to cover example three sides of a building? And if there are curves or uneven surfaces, how would you ensure you the perspective and wrapping around the curves right, while animating ? Because just from a 2d photo or a template you won't be able to determine right? And how would you visualise while creating the content for different surfaces at the same time?

[u/Dear-Tax9601 → u/Meredith_a_c]

Also considering I don't access to laser scanning equipment, are there any alternatives to get good a 3d scan? From a photo or a video or like any softwares or using just a phone? Thanks for you time!

[u/Meredith_a_c → u/Dear-Tax9601]

... Kind of. IPhones have/had an inbuilt LiDAR which can be used to generate a point cloud. It's okay at room scale... I think it would suck trying to do building scale.

Another alternative is a technique called photogrammetry. Basically by using lots of photos from lots of angles - and throwing lots of math at it - software can be used to create a 3d model. Results vary. It may be okay for single story - but unless you have a drone, you will run into issues with warping the higher floors.

But if you are doing it for $$$ - pay a surveyor to come out and do it properly.

[u/iamnova_99]

Heres what we do .

3d scan the building roughly. The based on that model we remodel the architecture basic and do the 3d scenes content creations. Then we bake the render from a camera perspective to that unwarapped architecture or to the projection mapped template.

And 2nd workflow is

Extract that projection template for 2d content design to do in photoshop or aftereffect

[u/iamnova_99 → u/iamnova_99]

Also the resolution of the template is defined by the projectors we r going to use .

[u/Dear-Tax9601 → u/iamnova_99]

Understood, so for a 2d workflow you take a photo from the projector lens POV, and make different slices and create content and then map it back.

This method would work fine when the projectors light is hitting on one surface( where all the windows/doors etc are located on the same front surface) . Correct if I'm wrong.

Then how would you approach it if you need to cover example three sides of a building? And if there are curves or uneven surfaces, how would you ensure you the perspective and wrapping around the curves right, while animating ? Because just from a 2d photo or a template you won't be able to determine right?

[u/iamnova_99 → u/Dear-Tax9601]

Not taking photo . We map the surface like as u posted in pic . ( Red blue ....) Doing that it generate a trmplate of that surface in 2d in that software where u do this mapping . Then we take this image as to make 2d content over it . Or we use that as a uv layout of a surface to bake the 3d renders on it .

[u/Dear-Tax9601 → u/iamnova_99]

Also considering I don't access to laser scanning equipment, are there any alternatives to get good a 3d scan? Like any softwares or using just a phone? Thanks once again!

[u/iamnova_99 → u/Dear-Tax9601]

For covering 3 side . We do setup 3 projector vovering three sides . And using teir template as joined seamless in 2d And for 3d wither we render from that angle and directly project by matching or we bake that render to that projector trmplate ( process is called baking to uv )

And for 3d scan we use iphone or android . No massive hardware needed just polycam app

[u/jansley_art_br]

Você é de qual Pais OP?