How do I crash a car?

mike_42547761

Okay, I have a feeling this is either going to be really simple or incredibly difficult.

I’m rendering a series of still images involving a car, that ends with the car crashing into a light pole. 

How do I do that? I want to make the hood crush and wrap around the pole.

Any help would be super appreciated.

Sfariah D

In real life it is easy but I think it is harder in Daz Studio.

Hylas

Use dForce. I wasn't successful in the one half-assed attempt I made (instead of crashing the car I crashed DAZ), but user Sven Dullah seems pretty good at it.

https://www.daz3d.com/forums/discussion/304901/does-dforce-suck/p2

Roman_K2

I had a very quick look at Sven's pictures and it seems to me that he is mostly staying with the basic mesh of the car.

The good news is we can maybe duplicate some of these effects.

Generally speaking this sort of thing is easy to do, but hard (read: time-consuming) for me to explain, so right from the get-go I'm hoping someone will step in with a better way.

Also, in-line graphics in the text of a message escapes me at the moment so I'm going to break this up into pieces -- similar to what Sven is doing, ha ha.

Roman_K2

The good news is that it is a lot easier to rip and mash things up, in DAZ-land, than it is to build something nice from scratch, or conversely to build a nice version of something that appears to be mashed up, from scratch. The sad news is that if you are doing a movie (say) then the crash site has to look good from all vantage points... here, I am only going think along the lines of, or as far as, making a nice crash scene in a single frame of a single "scene" if you will.

Ok, so drive carefully. Let's begin by accepting that the mesh of your average polygon vehicle looks something like this -

Roman_K2

There are of course many types of crashes, from relatively simple scenes like a fender bender or the driver loses control and drives into a lamp post or a telephone pole or some other obstruction.

Just staying with the "car" for now (as it is very easy to bend a telephone pole, in "Hexagon" which is DAZ's free modelling program) for the most part we are telling the visual story with some sort of ding or crumpling of the body of the car. Something like this, right?

Roman_K2

Ooooo, Val is going to be coming after me for this since I am always going on about never saying "Right?" to a beginner, and here I'm doing it myself!  Anyway yeah, so this is what we want to do - the car has to be damaged in some way, eg. some "dings" here and there, and/or there is some accordion-like deformation as the metal is smashed in.

Right off the bat there are several quick and easy approaches; I expect this is going to be a long thread so please feel free to chime in with your own methods and favorite tricks.

(Continued...)

 

SixDs

One of the difficulties in DAZ Studio is that everything is made out of "squishy" stuff. Rigidity, when needed, can be tricky, and a combination of rigidity and deformation even trickier.

As a first step, I would be inclined to find a picture of a real car that had hit a pole, for reference purposes. That will give you an idea of the dynamics that you are going to try and replicate. DForce may help, but it alone probably isn't going to produce believable results, IMO.

frankrblow

There are a few choices, and all of them need lots of work, but first off you need to decide on the details of what you want in the scene, as well as the specs for your computer. After all, there would be no point in using Studio if your computer can't handle the processes, in which case you'd need to use a modler (Hexagon, Blender, etc) to incrimentally reshape the vehicle.

Other choices: using deformers to create the damage effects; or turn the whole scene on its side and use dForce on the grill, hood, bumper only, while everything else has 'Visible in Simulation' turned off.

This is a little oversimplified, but it gives you an idea. And absolutely no guarantees any of it will work, but it may be worth a try.

I hope that helps a little. Once you decide, you can ask more specific questions of the experts - of which I'm not one 

Sven Dullah

...just a tip, if using dForce, export the car as .obj at base resolution (with all transforms values zeroed) and import as a morph. Every bone of the car will have its own slider, you might want to apply only 10% to the tires and 50% to the hip/main body or whatever;)

I also can imagine painting dFormer/push modifier weightmaps would work well for some scenarios...

mike_42547761

Thanks for the help from everyone. Much appreciatited. I look forward to tackling this later today.

Sven Dullah

SixDs said:

One of the difficulties in DAZ Studio is that everything is made out of "squishy" stuff. Rigidity, when needed, can be tricky, and a combination of rigidity and deformation even trickier.

Yup, trying to do this inside DS without the help of a modelling app is not an easy task, and dForce is cerainly not  meant to be used for crushing things. That's why I do it of course. As I mentioned in another thread, we need a dStroyer:)

SixDs said:

As a first step, I would be inclined to find a picture of a real car that had hit a pole, for reference purposes. That will give you an idea of the dynamics that you are going to try and replicate. DForce may help, but it alone probably isn't going to produce believable results, IMO.

Well...everything doesn't always have to be realistic IMO. And dForce can produce cool but somewhat unpredictable results, for sure Actually if you put time and effort into these kinds of experiments you can get quite nice things to happen.

dragonfly_2004 said:

 

Other choices: using deformers to create the damage effects;

dFormers definitely work, especially with weight maps, much easier to use than dForce.

dragonfly_2004 said:

This is a little oversimplified, but it gives you an idea. And absolutely no guarantees any of it will work, but it may be worth a try.

I hope that helps a little. Once you decide, you can ask more specific questions of the experts - of which I'm not one 

Not an expert either, just having fun:) I just had to try a push modifier, quite easy if the mesh is dense enough. But, as I've learned, it only works along the normals, so dFormers are definitely more versatile.

Quick push modifier experiment:

mike_42547761

Thanks again. Now I just need to find a good thread on how to apply deformers and magnets. Ithought it would be pretty straight forward, but nothing seems to be applying to my renders. 

mike_42547761

Thanks again everyone, your advice is working. Immattaching a quick open GL render so you can see what I'm doing. It's working out so far. Still lots of work as I have to create the rest of the scene such as people, objects, broken glass and setting, but I know how to do those things, so it shouldnt be too bad. 

Sven Dullah

mike_42547761 said:

Thanks again everyone, your advice is working. Immattaching a quick open GL render so you can see what I'm doing. It's working out so far. Still lots of work as I have to create the rest of the scene such as people, objects, broken glass and setting, but I know how to do those things, so it shouldnt be too bad. 

That looks cool! Glad you got things working:)

mike_42547761

Sven Dullah said:

mike_42547761 said:

Thanks again everyone, your advice is working. Immattaching a quick open GL render so you can see what I'm doing. It's working out so far. Still lots of work as I have to create the rest of the scene such as people, objects, broken glass and setting, but I know how to do those things, so it shouldnt be too bad. 

That looks cool! Glad you got things working:)

Couldn't have done it without you and the rest of the community!

Roman_K2

FWIW, I took the morphing plane (this is found in Maclean's Everyday Morphing Primitives set in the DAZ Store) and I laid it down over the hood of the test car. The morphing plane starts out as a sheet of... well, *nothing* but you can bend and twist it a bit and add some noise/irregularities. So I bent it slightly to more or less follow the hood of the car, and I dialled in some roughness. Then I shaded it and gave it a quick render, and I blurred some of the peaks and valleys using an image editor.

I'm no whiz at shading but you get the idea... it's a different sort of deformation process. For the next step you would cut out some of the dings and dents in an image editor, and you'd paste them onto the render of a crash (or junkyard) scene.

In this specific case I think the morphing plane needs to exported for a bit of smoothing, prior to it going back on top of the car for rendering, but for some reason the computer I'm using at the moment won't run Hexagon.

Syrus_Dante

I was following this thread with interest but had nothing to add.

@mike_42547761

Nice idea and looks good so far. Here are a few Tutorials I found:

D Former Tutorial- Screenshots

How to Use a Push Modifier: Creating a Blanket / Adjusting ...

Here is my short how-to for DFormers:

First thing I do with a dFomer is to parent the dFomer_Field to the dFomer_Base with drag&drop in the Scen pane. Its just easier to move them around all together with the universal translate tool gizmo. Then I translate the dFomer until the dots on the mesh are about where I want the deformation to be. Next I start to scale or tanslate the DFormer_Field for further adjustment, it can help to scale it up on one axis Y for vertical deformation and X for horizontal. If you start to scale or rotate the DFormer the placement of the DFormer_Base is used as the origin point.

If the default Shpere Influence Field deformation is not what you want you can open up the Tool Settings pane, switch the tool to Node Weight Map Brush, select the DFormer and press the button Add Map behind Unused Maps: Influence Weights. The initial weight map gets projected from the default sphere influence field. Now you can use the paint add/substract and smooth brush to define the weight map. Ofcourse you have to apply some transformation to the DFormer itself to see any effect.

Is almost like sculpting in 3D but better because you can always come back and manipulate the DFormer and the weight map. I've attached some screenshots and while doing I've discovered that I could add the SubD modifier to the pimitive plane and then I was able to paint the weight map on the subdivided vertices. First I coudn't belife my eyes for years now I paint weight maps on clothes without subdivision and if I do weight maps on figures I can only paint on the base mesh. When did they add this freature or why it dosn't work with figures is a mystery to me. See the attached screenshots maybe they can help.

On screenshot 10 I've added another DFormer. Then in Geometry Editor I've switched to Edge Selection mode and selected every second edge, then right-click select loop and so on. In the end I've got a zig-zag deformation that I painted irregularities ontop with the weight map brush. Later I've combined the mountain deformation of the other planes DFormer to the new plane with the DForm pane button Add Node where you can choose another DFormer in the scene to also have influence on more than one object.

Finaly you could "bake" the current deformation to a morph slider with the button Spawn Morph also found in the DForm pane. This should give you some ideas what is possible with DFormers and how you could further deform the car body.

Syrus_Dante

@Roman_K2

Looks like the morphing plane just needs to be set to high resolution (1 SubDivision Level) and it would look much smoother.

I don't like your suggestion about adding the bumps and dents in postwork, this would be the last thing I try if anything else failes.

The whole idea sounds very far-fetched at least doing it in Daz Studio. In another 3D modeling application like ZBrush this could be done. You could sculpt the bumps and dents on a primitive plane, render the grayscale height map in top view and use this image as a stamp brush tool on the subdivided car mesh. This workfow is what they call 2.5D. Another method would be to somehow project the shape of one mesh to another but non of this can be done in Daz Studio you may say.

This got me thinking of ways to render the morphing plane in top view as a grayscale height map to add it to the displacement map shader of the car lateron. Then I remembered that I saw this was done already somwhere.

I've serched my bookmarks and found this script from guess who mCasual mcjPlanarUV.

Here is how it could work:

1. in Daz Studio set the view to orthograpic left, right, front, back View should work and frame the view to the morphing plane Ctrl+F
2. run the script mcjPlanarUV that will save a new MorphingPlane.OBJ file to disc
3. now you can import the MorphingPlane.OBJ with the new UV into the scene and apply some of the gradient images mCasual provides on his site to the diffuse color (yes imported morphing plane now got DzDefault shader)
4. see what it looks like: the lower dents should now be black and the highest peaks should be white I guess
5. render the MorphingPlane.OBJ in top view (3Dlight I guess with only headlamp light no fancy shader)
6. use the rendered grayscale image as a base to create a displacement map for the car

...et voila - you get some kind of shape projection right within Daz Studio thanks to mCasual.

Roman_K2

Wow, no question that the deformer approach seems to be much more elegant in the long run. However in a simple scene involving say two figures and a car, and the woman appears to be angry with the guy because he put a ding in her car (car people are like that) doing it in 2D might be quicker in the short term.

Very interesting about the height and weight mapping... this being the "New User" section I'm not conversant with that stuff.  *I have* been to mCasual's page before.

I believe I mentioned that another approach or useful adjunct may be found in Iray "decals". Example: https://www.daz3d.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/r/iray-apocalypse-09-daz3d.jpg

I'm not sure I understand how this works.

Anyway, thanks for the detailed suggestions and great screenshots!